The chances to mistakenly leave the brake locked before removing the plate is very high because removing a chainsaw's sprocket plate is the first step in several frequently-performed chainsaw repairs and maintenance procedures.

This little oversight can get the best of even the most careful tool users.

We explain the steps to reinstall a locked chainsaw sprocket plate below because knowing how to quickly get that plate back on your saw can turn your unlucky day around.

Watch this article's video to see a demonstration of the repair steps.

Steps to Install a Locked Sprocket Plate

Remembering to unlock a chainsaw brake before removing the sprocket cover is such an important check to make because locked sprocket plates do not reinstall on their chainsaws easily.

This mistake only happens on chainsaw models where the saw's brake mechanism is actually part of the sprocket plate (like the saw pictured above), but this is the case for many models.

Basically, the matched brake mechanism dogs on the plate and the saw must be forced together while pulling on the brake lever to unlock them.

1. Remove the chainsaw chain and bar.

It is difficult or impossible to install the locked sprocket plate on the chainsaw with the chain and bar still on the bar.

Remove the bar and chain and set them aside until the brake mechanism is unlocked later in the repair.

2. Lay the chainsaw on its side.

Lay the chainsaw down with its sprocket plate side up.

This will make it possible to exert the pressure on the sprocket cover needed to force the brake mechanism back together.

3. Force the brake mechanism dogs together by firmly pressing down on the sprocket plate.

Line up the sprocket plate into its correct position and press down very firmly on the brake mechanism area.

4. While pressing, unlock the brake by pulling the brake lever.

Your pressure on the brake mechanism should force it open when you simultaneously pull the brake lever into the unlocked position.

5. Reinstall the bar, chain, and unlocked sprocket plate.

Please visit the article links below for help with these assembly steps:

How to Remove and Install a Chainsaw Chain

How to Tighten a Chainsaw Chain

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Conclusion

Forcing the brake to unlock like this can be hard on parts of the mechanism, so it's best if you get the sprocket plate unlocked on the first attempt.

If the problem your saw is experiencing goes beyond the scope of this specific repair article, type your saw's model number in the search field at the top of this page to visit your saw's parts page. Your saw's parts page will have a breakdown schematic available for viewing.

Find more chainsaw parts on our Chainsaw Parts page here at eReplacementParts.com

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What we're about.

Properly cleaning a 2-cycle engine carburetor means completely disassembling and reassembling the unit.

We explain the steps to disassemble and reassemble an example 2-cycle engine carburetor below, and we also explain the correct way to clean a carburetor while it's still disassembled.

Watch this article's video for a professional demonstration of the procedure!

Carburetor Disassembly Steps

This carburetor disassembly, cleaning, and rebuild demonstration is performed on a carburetor from a Ryobi 2-cycle grass trimmer. Steps for other carburetor cleanings will be similar to these.

Tip! Carburetors have many small parts. Keep carburetor parts organized in the order that they are removed (like in rows) to make reassembly fast and accurate.

The Bottom Side of the Carburetor

1. Remove the bottom plate.

Unscrew the two screws that affix the lower cover plate to the carburetor body.The bottom plate is held on by four screws for some carburetor models.

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2. Remove the diaphragm and diaphragm gasket–separate them if needed.

The carburetor diaphragm will come off easily after the bottom plate is removed.

The diaphragm gasket will often stick to the diaphragm when removing it from the carburetor body. If the diaphragm and diaphragm gasket are stuck together, they must be carefully separated from one another to be cleaned later. 

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3. Remove the needle valve mechanism.

The needle valve mechanism consists of three parts: a needle, a lever, and a spring.

It will be visible in the body of the carburetor after the diaphragm is removed.

The needle valve mechanism is held into place by a retaining screw.

Unscrew the needle valve retaining screw to release the mechanism from the body of the carburetor.

Make sure to hold the spring-loaded mechanism in place as you remove the screw. This will stop the valve parts from flying across the workbench.

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The Primer Bulb Side of the Carburetor

Remember to keep the carburetor parts organized as you go. This is a good place in the disassembly to start a new row of parts.

4. Remove the primer bulb and its retaining plate.

The primer bulb is held onto the primer base with the help of a retaining plate. Two screws affix the primer bulb retaining plate to the primer base.

Remove the two screws that hold the primer bulb retaining plate to the primer base.

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5. Push the primer bulb from its retaining plate.

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6. Remove the primer base and carburetor reed valve.

Removing the primer base retaining screws frees up the primer base from the carburetor body.

Set the primer base aside for cleaning. Look for a thin reed valve piece between the primer base and the carburetor body.

Handle the reed valve piece with care. It is important to the operation of the carburetor and very delicate.

If a fragile piece like this one is damaged on a carburetor that lacks a rebuild kit, the entire carburetor will most likely have to be replaced.

After following these steps, all the small pieces of the carburetor are now removed from the carburetor body and are ready for cleaning.

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How to Clean a Carburetor

For this part, you'll need:

• a pan
• a can of carburetor cleaner
• a towel, and
  
• compressed air (if available)
  

The procedure for cleaning each part of the carb is the same:

1. Clean the outside of the part. 

2. Clean the inside of the part.

3. Dry the part.

4. Be very careful with sensitive parts. 

Start with the body of the carburetor and don't be afraid to use a lot of cleaner on it.

Take advantage of the openings in the carburetor body to clean its fuel pathways.

Make sure to point orifice outlets away from you when you do this!

Thoroughly air dry the carb body with compressed air (f compressed air is available) and set in on a towel to continue drying.

Move on to the other durable pieces of the carburetor.

The internal orifices of the primer bulb base require cleaning just like those of the carburetor body.

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Cleaning Delicate Carburetor Components

There are a few pieces of the carburetor that need extra consideration when cleaning them, including the reed valve piece, the screen filter on the carburetor body (see below), and the carburetor diaphragm.

•  That thin reed valve piece that goes between the carb body and the primer base must be cleaned and handled carefully.

Use as little carburetor fluid as possible and spray it at low pressure to avoid damaging the piece.

Quickly dry the reed valve on a clean towel after gently spraying it with cleaner.

• Many carburetor designs include a small screen filter on the carburetor body.

This filter is easily damaged when removed. Leaving it in place is usually the best choice when replacement filters are not available.

• The carburetor diaphragm is another piece that is often too delicate for rigorous cleaning.

The diaphragm is made of thin rubber in the case of our Ryobi demonstration carburetor. Because rebuild kits aren't available to replace it if it were damaged during cleaning, it should only be cleaned when absolutely necessary.

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Steps to Reassemble the Carburetor

Most of steps to reassemble a carburetor are self-explanatory in that you simply replace components in the reverse order that you removed them.

Replacing the needle valve mechanism is the trickiest step when reassembling the Ryobi 2-stroke engine carburetor that we use for demonstration in this article. 

Here are the steps for replacing the needle valve mechanism:

1. Place the needle on the lever.

This carburetor's needle valve lever has a forked portion on it. The top of the needle fits into the forked portion of the lever as pictured below.

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2. Replace the needle valve spring.

Just place the spring back into it's slot in the carburetor body.

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3. Drop the needle into the valve jet.

The needle valve lever will rest on top of the spring when the needled is dropped into position.

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4. Reinstall the needle valve retaining screw.

Hold the needle valve mechanism in place with your finger once it is aligned into position.

Return the valve retaining screw while holding the mechanism down.

The rest of the carburetor reassembly should be pretty straight forward if care was taken to keep parts organized while it was dismantled. 

Watch this article's video demonstration of this procedure for detailed reassembly steps!

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Ryobi Carburetors and Cleaning Maintenance

Owning a Ryobi gas-powered tool is usually a good reason to perform a carburetor cleaning without the help of a rebuild kit. This is because carburetor rebuild kits are not available for most Ryobi 2-cycle tools.

Carburetor rebuild kits include replacement parts for many of a carburetor's small, inexpensive, easily-worn parts. When used in a traditional cleaning and carb rebuild, these kits get an old carburetor running like new with little effort on the part of the tool owner.

Additionally, the availability of replacement carburetor parts takes some pressure off of the person performing the rebuild, because delicate parts that may be accidentally damaged during the rebuild can easily be found and reinstalled.

Maintaining the life of a carburetor takes extra care when carburetor rebuild kits are not available, like in the case of Ryobi tools.

When the small parts of the carb can't be replaced inexpensively, the best way to maintain the performance of the carburetor is to dismantle and carefully clean each part.

Carburetor rebuild kits can occasionally become unavailable for tools of every make, but we chose to perform this article and video's demonstrations on a Ryobi carburetor because of how commonly rebuild kits are not available for them. 

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Conclusion

If you're looking to check the availability of carburetor rebuild kits for your gas-powered tool, type your tool's model number in the search field at the top of this page.

Your tool's parts page will have available rebuild kits listed on its parts page just below its breakdown diagram!

You can also search for carburetor rebuild kits by visiting our Small Engine Parts page here at eReplacementParts.com.

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What we're about.

Damaged mower blades can cause excessive vibration in the mower, while dull mower blades usually get noticed by the ugly, irregular patterns they make in the lawn.

Mower blades can be sharpened several times to extend their life and ensure that your grass gets a healthy cut, but they can only be filed so many times before a blade replacement is necessary.

Homeowners can save themselves quite a bit of money performing simple repairs like this one. New mower blades tend to be reasonably priced, and mower blade replacements usually only require the use of a wrench.

For information about matching a replacement mower blade to your mower, please read our article, Lawn Mower Blade Measurements and Types.

Steps to Replace a Lawn Mower Blade

Mower blade mounting designs vary, but the basic steps are usually the same. Most mowers have use a very simple blade mounting design like the mower we use below as an example .

1. Set the mower on its side.

 Always set the mower on the side that does not have a carburetor so that the mower's fuel does not leak out.

Make sure the gas and oil caps are screwed on tightly before tipping the mower.

2. Remove the fasteners holding the mower blade on.

This just means removing one nut on our example mower, and this is usually the case for most mower models.

Use one hand to steady the blade when first loosening the nut.

3. Remove the old mower blade.

Make sure to hang on to any mower pieces that help mount the blade, like the retaining plate pictured below.

4. Install the new blade.

Most mower designs will not allow the mower blade to be installed with the wrong side down.

Our example mower blade and its retaining plate are shaped so that the blade can only be installed in the correct position.

It is possible to incorrectly install mower blades on some mowers. And it's always possible to install a blade too loosely.

Vibration and poor lawn cutting will quickly make a poor mower blade installation noticeable. A quick adjustment is all it takes to get back to work in the event of an incorrect installation.

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Conclusion

The surprising thing about this repair might be how easy it is, especially since many lawn mower owners do not take the opportunity to save money on tool repairs by doing them at home.

If your mower blade is dull, damaged, or heavily worn, visit our eReplacementParts.com Lawn Mower Blades page to start your search for a compatible match and get started with this fast and easy repair.

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What we're about.

We show how to get the right replacement pad for a sander and the best way to install it on its sander using the Porter Cable 333 Random Orbit Sander as an example.

Match the Right Pad to the Sander

Backer pads can have different numbers and orientations of vacuum holes and mount holes depending on the make and model of the random orbital sander.

Accordingly, the hole configurations on backer pads must match thoseof their sanders.

The Porter Cable 333 in our example has five vacuum holes and three mount holes. Some sanders are designed with six or eight vacuum holes, and some have four mount holes instead of three.

The easiest and most accurate way to order a new backer pad for your random orbit sander is to use the sander's model number.

Type the sander's model number in our "Model Number" search field at the top of the page, and your browser will direct you to your sander's parts page.

Only compatible O.E.M. backer pads will be listed on a sander's eReplacementParts.com parts page.

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Sander Pad Replacement Steps

1. Unscrew the sander pad mounting screws.

2. Remove the old pad.

Remove the mounting screws from the old backer pad as well.

3. Install the new pad.

We find that it's much easier to first place the mounting screws inside the new backer pad's mount holes. With the screws in, align the backer pad on the sander and thread the mounting screws.

4. Tighten the mounting screws down.

It's best to first mostly tighten all the screws before giving them those last couple turns.

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Conclusion

Visit our Sander Parts page to find your random orbit sander backer pad by brand name, or enter your sander's model number in the search field at the top of the page.

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What we're about.

The usefulness of primer bulbs is often under-appreciated until tool users go to start their machines and find their engine's primer bulb excessively worn, broken, or cracked.

Cold starting a gas engine without a fresh squirt of fuel in the carburetor is difficult to say the least.

Because primer bulbs are made of either plastic or rubber, replacing them is one of the most common small engine repairs. Tool owners should expect primer bulbs to eventually wear out.

Steps and examples for two common types of small engine primer bulb replacements are explained and listed below.

Reasons to Replace a Primer Bulb

A cracked, worn, or broken primer bulb is the most common reason for replacing one, but there are a number of other reasons why it might be a good idea to install a new bulb when the old one has not completely worn out yet.

• When replacing fuel lines:

If you're performing a fuel line repair on your tool's engine, it's most likely because the plastic fuel lines are cracked with age or wear. Because plastic fuel lines and primer bulbs are usually the same age, they work as good barometers for each other's wear.

In other words, if one wears out and cracks you can expect the other to follow soon.

Since a fuel line replacement requires a parts order and work in that part of the engine, it just makes sense to order a primer bulb at the same time to save money on shipping.

• When cleaning the carburetor:

Primer bulbs are often located on or near an engine's carburetor. Especially in the case of primer bulbs located on the carburetor, you can save yourself time on future repairs by replacing the bulb when dismantling and cleaning the carburetor anyway.

• When performing any other work on the engine's fuel system:

If it's been more than a season or two since your tool's engine got a new primer bulb, you'll thank yourself later for replacing it pretty much any time you have a good excuse.

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Primer Bulb Mount Types

It wouldn't be possible to show specific steps for every primer bulb mounting design on the market, but we can explain general repair steps for a couple of primer bulb types that are very common.

Even though small differences will exist between each specific engine's primer bulb design, primer bulb repairs share similar qualities.

It's probable that seeing the steps for replacing the bulb in one design will help you to replace the bulb in another kind of engine.

We list and explain the steps for replacing two types of primer bulbs below, designs where the primer bulb mounts directly on the engine's carburetor, and designs where the primer bulb mounts remotely from the carb.

We use two different trimmers for our demonstration examples below, a Shindaiwa T242 Trimmer and a McCulloch trimmer.

Because both demonstration models are 2-cycle trimmers, the repair steps and demonstration video in this article will be most helpful with primer bulb replacements on power tools designed with 2-cycle engines.

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Primer Bulb on Carburetor Repair Steps

Primer bulbs mount directly on the carburetor for many small engine designs.

Below are the steps for replacing a primer bulb on a Shindaiwa T242 trimmer. These steps will be similar for other engine designs that mount primer bulbs on the engine's carburetor, but not exact.

Reviewing these steps will likely help with primer bulb replacements on other engines.

1. Access the carburetor.

To remove the old primer bulb, the trimmer's carburetor must be accessed.

The first steps toward accessing the carburetor are to remove the air cleaner cover and the air filter.

2. Unscrew the two carburetor mount screws.

The entire carburetor assembly will pull away from the trimmer after the two mount screws are free. Pull the choke plate away from the carburetor and set it aside.

The carburetor is now completely accessible.

3. Remove the old primer bulb.

The Shindaiwa T242 has four screws that mount the primer bulb plate to the carburetor. These must be unscrewed.

Be prepared for a little gas to leak out after the fourth screw is released. Once away from the carburetor, the old primer bulb should easily pop right out of the mount plate.

The old primer bulb is now removed.

4. Clean the carburetor and primer bulb components.

Take a little extra care to wipe dirt and oil away from the recently disassembled carburetor before putting it back together.

5. Install the new primer bulb.

For the T242, the primer bulb can be pressed into place in the mount plate from which the old bulb came.

Before the primer bulb plate can be screwed back into place on the carburetor, the pieces of the disassembled carburetor must be reassembled in the correct order.

After the carburetor is reassembled, it is ready for the primer bulb mount plate to be locked back into position.

6. Remount the carburetor.

Insert the two carburetor mount screws through the carburetor choke plate and the carburetor. Then entire assembly can then be attached to the engine.

Then entire assembly can then be attached to the engine.

Then the mount screws just need to be tightened down again.

7. Replace the air filter and air cleaner cover.

This primer bulb replacement is now complete.

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Remote Primer Bulb Repair Steps

Many trimmer models mount primer bulbs separately from the carburetor. Most remote-mount primer bulb designs use a snap and ring system like the trimmer in our example.

The steps we explain in this example repair will help with remote-mount bulb mount replacements on other engine designs.

1. Clamp the return fuel line.

Clamping the fuel line leading out of the primer bulb will prevent excess fuel leaking during the repair.

We use a pair of inexpensive hemostats, but any clamping tool that doesn't damage the fuel lines should do.

2. Remove the fuel lines from the old primer bulb with a screwdriver.

3. Remove the old bulb by squeezing its mount tabs.

Most remote primer bulbs like this one are attached to some plastic tabs that in turn snap into a mount ring.

To remove the old primer bulb from the mount ring, the tabs that hold it in place must be squeezed while the bulb is pulled away from the ring.

A pair of needle nose pliers works best for this.

4. Install the new primer bulb.

The mount tabs on the back of the new primer bulb should snap right into place in the mount ring.

Sometimes the tabs can be a little too tight to snap in by hand. Try turning the engine (if possible) so that gravity is on your side, and then carefully use a flat head screwdriver to press the mount tabs inside the mount ring.

5. Reinstall the fuel lines.

Press the fuel lines onto the new primer bulb by hand, and then unclamp the return line.

This primer bulb replacement is now complete.

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Ryobi Trimmer Primer Bulbs

Since we're on the subject of primer bulb replacements in general, we'll take a minute to clear up a common question concerning Ryobi brand trimmers and their primer bulbs.

Like the primer bulbs of all gas engines that have them, Ryobi trimmer primer bulbs eventually wear down, crack, and must be replaced.

Also, Ryobi trimmer primer bulbs are mounted directly to their carburetors, similar to the Shindaiwa trimmer used in this article's first example.

Unfortunately, Ryobi does not distribute individual primer bulbs for sale. The only way to purchase an O.E.M. replacement primer bulb for a Ryobi trimmer is to purchase an entire carburetor assembly for the engine. Ryobi does not offer primer bulbs for their trimmers that are separate from the the carburetor assemblies.

Because O.E.M. parts replacement is the only way to guarantee an accurate parts match and proper tool operation, eReplacementParts.com does not recommend any other avenue for replacing a Ryobi trimmer primer bulb other than to buy the entire carburetor with which it is included.

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Conclusion

In only takes a few minutes to replace a primer bulb, especially after you're used to your engine's primer mount design. After getting gas on your hands a few times through a cracked bulb, a small repair like this one can make you feel like you have a whole new engine.

Start your primer bulb repair by entering your tool's model number in the Search by Model Number field at the top of the page.

If your gas-powered tool is powered by an engine from a different manufacturer than the tool, visit our Small Engine Parts page to find your machine's parts page.

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What we're about.

When the time comes to replace a Honda engine's filters, spark plug, or any other part, making a correct engine number match is the key to accurate parts replacement.

We explain what Honda small engine owners need to know to ensure an accurate engine parts matches every time.

Honda Small Engine Number Matching

Two numbers must be found on the engine to ensure an accurate Honda small engine parts match:

1. The engine's model number must be matched, and

2. The engine's VIN number must be matched.

We'll use the Karcher pressure washer pictured below as an example of how to find a Honda engine's model and VIN numbers.

This pressure washer is a good example of a Honda small engine in use with another company's tool.

The majority of Honda engines in service power the tools and machines of other manufacturers. When Honda engine owners need parts for their small engine, it is very important that the use the engine's model and VIN numbers to match engine parts, not the tool's identifying numbers.

For example, using the tool model number of our example pressure washer to search for its engine parts will not be successful. The tool model number will only lead to parts for the Karcher pressure washer, not the engine that powers it.

Engine model and VIN numbers must be found on the engine.

Honda Small Engine Model Numbers

The model number is the easy one to find. Honda small engine model numbers are (almost always) very clearly displayed on the front of the engine.

So, "GC190" is the model number for this Karcher pressure washer's Honda engine.

Honda small engine model numbers always start with one or more letters.

Letters at the beginning of Honda model numbers indicate the "series" to which that engine model belongs. So, the Honda GC190 engine is part of the Honda GC engine series, and "190" is the engine model number in that series.

Having the engine's model number is the first step towards an accurate Honda small engine parts match.

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Honda Small Engine VIN Numbers

Honda VIN numbers add an extra level of accuracy to engine parts matching. Using both the engine's model and VIN numbers when finding parts for your engine guarantees a match.

Unlike their model numbers, Honda engine VIN numbers can be just a bit harder to find and read. A Honda engine's VIN number is stamped somewhere on the engine.

Here are some things to know about finding and reading Honda small engine VIN numbers:

• It can be stamped almost anywhere on the engine.

• The VIN number will consist of 3 sets of characters that can be both letters and numbers, can be arranged in a variety of ways, and can consist of a few or several characters per number set.

• Honda engine VINs usually start with one or more letters.

• Although they are stamped permanently, Honda VINs are almost always stamped very lightly and in a dot pattern, making them difficult to read.

In the case of the our example pressure washer, the engine VIN number is stamped on the side of the engine right next to the housing.

As you can see, the VIN number is also stamped sideways on the engine. Let's flip that picture around, zoom in, and take a look at the number's legibility.

It's hard to explain exactly what we mean here with just a picture, but you can see that the number is hard to read even with a large, bright, focused photograph.

Hint: You can apply a liquid to the stamped VIN number to make it more legible.

Applying different liquids to the stamped number can cause the light to hit the impressions a little differently, cause more of a contrast, and make the VIN number more readable. 

We know it might sound strange, but a little carburetor cleaner seems works best for us. Take a look at the picture of the same Honda engine VIN number below after a little shot of cleaner.

Any liquid will at least improve the VIN number's legibility, including water.

The VIN number on this engine is : GCAAA-1518947-QHAF

It's also possible that the VIN number on your Honda small engine is legible without any assistance. In either case, finding and correctly reading your engine's VIN is absolutely necessary for an accurate parts match.

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Conclusion

Once you have your Honda small engine model number and VIN number, you can type either number into the eReplacementParts.com "Search by Model Number" field at the top of this page. Your search will take you directly to matching Honda engine parts pages.

With accurate number matching, finding the right Honda small engine parts for your machine is made easy with our parts lists and interactive breakdown diagrams.

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What we're about.

A mower's owner's manual will indicate how often to perform oil changes on the mower. At the very least, an oil change should be done annually with other seasonal tune-up maintenance.

This article explains the steps for changing oil in most mowers. Changing mower oil is very simple and can take as little as five minutes.

Prepare for the Oil Change

There are a few things to do before removing the old oil from the mower.

1. Warm up the engine

Warming up the mower engine will speed up the oil change because the oil will flow more freely. It will also be a little easier to get all of the old oil out of the engine.

2. Clean around the oil fill area.

Use an air compressor or a clean towel to clean up around the oil fill area.

3. Prepare an oil pan to catch the oil.

You'll need an oil pan or something similar to catch the oil from the mower. Position the pan on the side of the mower towards which you will tip it to drain the oil.

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Dump the Old Oil

Now with the prep work done, the mower should be ready to have its oil drained.

4. Remove the oil fill cap.

5. Tip the lawn mower on its side to drain its oil.

It's a good idea to leave the mower resting on its side for about a minute while all of the old oil drips out.

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Replace the Oil Filter (if applicable)

The majority of walk-behind lawn mowers do not have oil filters, but several models on the market include them in the engine design. We've included the steps for changing a mower's oil filter below in case your mower model includes one.

If your lawn mower engine model does not include an oil filter, skip to step Step 10 to complete your oil change.

6. Prepare something to catch the oil.

Unscrewing your mower's oil filter will spill the oil it is holding inside of it.

Find something to catch the oil that is small enough to fit under the filter as you unscrew it.

7. Unscrew the old filter.

The old filter simply unscrews.

8. Coat the seal of the new filter with oil.

The seal of the new oil filter needs to be coated with oil before it is installed.

Using your finger, apply a small coat of motor oil to the outside lip of the new filter. This thin coat of oil will ensure that it seals tightly when you install it.

9. Install the new oil filter.

Screw the new oil filter into place until it touches the plate it seals against. Then, give the filter a firm 1/4 or 1/2 turn to tighten it down.

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Refill Mower Oil

Now the mower is ready to have its engine oil refilled. Remember that over-filling the oil on a lawn mower engine is just as bad as under-filling it.

Check the mower owner's manual for the exact quantity of oil that the mower takes.

Use the mower's dipstick as the final judge on the right oil level. Most mowers take between 2/3 and 3/4 a quart of oil

10. Add engine oil gradually until it is full.

Stop a couple of times as you fill the oil to check its level with the dipstick.

Creeping up on the "full" line like this reduces the chance of overfilling.

11. Replace oil cap.

Your lawn mower oil change is now complete.

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Conclusion

Changing your lawn mower's oil will help its engine run powerfully and dependably. This and other simple equipment maintenance will greatly extend the life of your tools.

eReplacementParts.com can help you with your lawn & garden machine repairs. Visit our Lawn Mower Parts page to shop for parts by mower brand, or visit our Small Engine Parts page for more small engine maintenance parts.

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What we're about.

This means that special 2-cycle engine oil must be mixed with the gasoline in 2-stroke engines in order for them to stay cool during operation.

Running a 2-cycle engine with the wrong gas/oil mixture can seriously damage your equipment, and running one without any oil in the fuel will completely destroy your tool's engine in minutes.

Many tool users have questions about oil/gas mixtures in 2-cycle engines, and many engines require different mixture ratios.

This article explains what tool owners need to know to properly mix oil into the fuel of their 2-cycle engine equipment. Mixing steps, engine mixture ratios, gasoline storage procedures, and damage prevention tips are explained below.

How Long Does Gasoline Keep?

Using "new" gasoline in a gas-powered engine isn't always the same as using fresh gasoline.

The gas you pour into your equipment's fuel tank might be "new" because it just came from the gas can, but how long has the gasoline in your can been sitting there?

Many tool owners are unaware that gasoline expires. The general rule of thumb is that gasoline can store for three to six months before becoming unhealthy for use in engines.

After a few months, gasoline begins to break down and loses the full potency of its combustible properties.

Using old gasoline will reduce the power output of your tool's engine, and it can also cause excessive build-up of impurities in an engine's parts.

Here are some tips for proper gasoline storage and use:

• Discard gasoline after storing it for three to six months. Discarding any remaining gasoline in your garage or shed at the start of each season is a smart habit to develop.

• If you store your gas-powered equipment with fuel inside their gas tanks, use a fuel stabilizer to protect the carburetors of your tool engines.

• Even if you use a fuel stabilizer in your tool engines when you store them, discard the gasoline at the start of the next season. It's only there to keep your carburetor from drying up.

• If you're determined to store gasoline for long periods of time, use a fuel stabilizer. Many tool owners mix stabilizer in their fuel just as a general practice. Fuel stabilizer can extend the life of stored gasoline up to several more months.

We mention this gasoline storage issue in this article because taking all the care in the world to mix oil correctly in your 2-cycle engine will only solve one problem (lubrication).

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2-Cycle Oil/Gas Mixture Ratios: Then and Now

Every 2-cycle engine has a specific gas/oil mixture ratio, so the first step in mixing your 2-cycle engine oil is determining the correct ratio for your tool's engine.

Most 2-cycle tools display the correct gas/oil ratio somewhere on the tool, usually the engine housing. If not, the tool's owner manual will have the ratio information. If the tool's owner manual is misplaced, most manuals can be accessed on manufacturer websites.

Measuring for 2.6 Ounces of 2-Stroke Oil

Almost every newer 2-cycle engine uses a 50/1 gas to oil ratio, as opposed to older tools that use more oil. This is because the lawn & garden industry is designing cleaner-running gas engines. 

Older gas-powered tools may use gas/oil ratios of either 40/1 or 32/1.

Here's the catch: because the industry is shifting heavily towards 50/1 ratio 2-cycle engines, most of the 2-cycle engine oil products available on the market today are sized so that an entire bottle can be conveniently added to round gallon figures (like 1 gallon), producing a 50/1 mixture.

For example, the 2-cycle engine oil products pictured below come in 2.6 oz. bottles. 2.6 ounces of oil is exactly the quantity needed to produce a 50/1 mixture with exactly 1 gallon of gasoline. Larger, 6.4 oz. 2-cycle oil bottles are also available for mixture with exactly 2 and 1/2 gallons of gasoline, again producing a 50/1 mixture.

Because the 2-cycle oil market favors container sizes geared toward 50/1 gas/oil mixtures, you will have to do some extra careful measuring if your 2-cycle engine accepts a 40/1 or 32/1 mixture. 

Most of the oil bottle sizes on the market are 2.6 ounces (for 1-gallon 50/1 mixtures).

Because it is much easier to accurately measure larger volumes of gasoline (as opposed to small volumes of oil), we've expressed our measurements for 40/1 and 32/1 mixtures below so that tool owners can simply add an entire 2.6 oz. bottle of oil to a modified quantity of gasoline.

Measuring out the gasoline is much easier than measuring out the oil. 

One last comment. The best case scenario is obviously a precise mixture measurement. That being said, it's always best to mix more oil than less oil if you're unsure.

50/1 Mixture Measurements:

2.6 ounces of 2-cycle oil / 1 gallon of gasoline

40/1 Mixture Measurements:

2.6 ounces of 2-cycle oil / 0.8 gallons (approx. 103 ounces) of gasoline

32/1 Mixture Measurements:

2.6 ounces of 2-cycle oil / 0.65 gallons (approx. 84 ounces) of gasoline

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2-Cycle Engine Oil Mixing Steps

2-cycle engine oil must be mixed with gasoline in a separate gas container in order for it to mix correctly.

Never mix 2-cycle oil directly into the fuel tank of your tool's engine.

Here are the steps:

1. The oil should always be added first.

Pour the correct, pre-measured amount of 2-cycle engine oil into a clean, appropriately-sized gasoline container.

2. Add the correct amount of gasoline to the oil.

3. Seal the gas container and gently swish it until the oil completely mixes. Do not shake the gas container.

These steps are very simple, but it's still important to take care to perform them in the correct order.

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2-Cycle Oil and Engine Damage

Mixing too much oil in your 2-cycle engine is much less damaging to the engine than mixing too little oil. If there's only a little too much oil in the mixture, you may not notice any difference in your tool's performance at all. The important thing is that it's being lubricated. 

If a lot of extra oil is mixed in the fuel, there are some symptoms that might appear:

• smoky exhaust
• oil out the muffler
• loss of engine power

Fixing any of these problems is as easy a discarding the over-oiled fuel and replacing it with fuel mixed at the proper ratio.

Mixing too little oil in your 2-stroke engine is very dangerous for your tool's engine. Running a 2-cycle engine without any oil in the fuel will completely destroy the engine in minutes.

The engine's piston and cylinder become extremely hot without lubrication through the fuel system.

Without any oil at all, the metal of these precisely-shaped and -sized parts actually melts and then transfers material back and forth between the piston and cylinder. When metal transfers between the moving parts of an engine like this because of heat, it is called galling. Galling distorts the shapes of the piston and cylinder.

You'll know that it's happened almost immediately, because the engine will seize and become permanently unusable.

Mixing too little oil in you 2-cycle engine will similarly damage your tool's engine, but over a longer period of time.

Lack of engine power is the most prominent sign that a 2-cycle engine is running on too little oil. Permanent damage can be prevented if the problem is corrected early, but such an outcome would be very fortunate.

This is why it is so important to mix your 2-cycle engine oil at the correct ratio for your tool. Using fresh fuel and the correct oil/gas mixture ratio prevents all of these potential problems.

Watch this article's demonstration video to see what happens when a 2-cycle engine is run without oil in the fuel:

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Conclusion

eReplacementParts.com stocks parts for thousands of 2-cycle engines and other Small Engine Parts used in power tools and equipment of all kinds.

Our website's breakdown schematics, how-to articles, and Repair Forum are here to give tool owners all the information tools they need to keep their engines running at a level of professional maintenance.

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What we're about.

A malfunctioning ignition coil is a common reason for why a gas-powered engine might not fire up right away (or at all). Ignition coil modules must be replaced when they go out.

Using a two-cycle line trimmer as an example, this How-to article and its accompanying video will show you how to replace an ignition coil in a gas-powered engine. In addition, we'll offer some advice for diagnosing potential ignition coil failure on practically any gas-powered engine.

Many tool repairs can be performed right at home, saving you the time and money that would otherwise go to a repair shop. Even repairs that require some dismantling and specific steps can be a cakewalk for  tool users equipped with the right know-how.

Ignition Coil Function and Diagnosis

Ignition coil modules rest closely to an engine's flywheel. Flywheels have a magnet on them that passes the ignition coil module as the flywheel spins.

The passing flywheel magnet generates an electric charge inside the ignition coil module, and the module transfers that charge to the engine's spark plug. It's easy to see why a healthy ignition coil is necessary for an engine to start and run at all.

In addition, the mechanism inside the ignition module is set on a timing sequence that coordinates with the speed of the turning flywheel's passing magnet. Sometimes an ignition coil will fail simply by being out of sync with the timing of the flywheel.

A mistimed ignition coil may not fail completely. In other words, the engine may still run, but run poorly.

In any case, testing an engine's ignition coil is a smart diagnosing step if your gas-powered tool isn't starting or if it is running irradicably.

It might be a good idea to eliminate other possibilities first, such as carburetor problems, clogged filters, bad spark plugs, and fuel lines.

Testing an ignition coil requires a special diagnosing tool called a spark tester. Spark testers are inexpensive and easy to use.

Here are the steps for using a spark tester to diagnose an ignition coil:

1. Remove the engine's spark plug boot.

2. Attach the boot end of your spark tester to the engine's spark plug.

3. Insert the other end of the spark tester into  your engine's  spark plug boot.

4. Pull the engine's starter rope.

The spark tester breaks (and then completes) the circuit from the ignition coil to the spark plug. Once the spark tester is positioned correctly and securely, give your engine's start cord a few pulls.

If the ignition coil is working properly, then the window on the spark tester will light up with electrical charge when you pull the start cord. If the spark tester window does not light up when you pull the start cord, then you can be sure that your ignition coil needs to be replaced.

Replacing an ignition coil requires a little dismantling and is a more invasive engine repair than average, so it's best not to just guess when it comes to replacing your coil.

Spark testers can be found an purchased as most hardware stores.

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Ignition Coil Replacement Steps

We replace the ignition coil on a Shindaiwa T242 EPA2 Gas Trimmer for this demonstration.

Getting the right ignition coil for your machine is truly the first step for this repair. Use your tool's model number in our "Search By Model Number" field at the top of the page to navigate to your machine's parts list and breakdown diagram.

View this Shindaiwa trimmer's ignition coil page by clicking here.

Here are the steps for replacing this trimmer's ignition coil. The following steps will be very similar for all gas engine makes and models:

#1 Disassemble the Trimmer

Most (or all) of an engine's housings and shrouds should be removed to perform this repair. A driver for your tool's fastening system (torx, phillips, hex, etc.) is the only tool you need for this step.

1. Remove the spark plug boot.

2. Remove the air filter housing. 

3. Remove all other trimmer engine shrouds.

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#2 Remove the Old Ignition Coil Module

The ignition coil will be attached to your engine in three ways: with fasteners holding the module to the engine, ignition wires connecting to the engine, and at the spark plug boot.

You'll need a couple pairs of needle nose pliers and a screwdriver for these steps:

1. Using two pairs of needle nose pliers, disconnect the ignition wires from the engine.

2. Make sure the spark plug boot is disconnected.

3. Unscrew the fasteners holding the old ignition coil to the tool's engine.

Your old ignition coil is now freed up and can be removed.

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#3 Transfer Module Components to New Module

Your new ignition module will most likely be missing a couple of small components. Don't worry; components from the old module are meant to be transferred to the new module.

Four parts must be transferred from the old ignition coil: the spark plug boot, the spark plug coil spring, the ignition wire protective heat shield, and the ignition wire itself. Sounds complicated maybe, but it's actually very easy. Make sure to assemble the components on the new module in reverse order that you removed them from the old module.

Here are the steps:

1. Pull the spark plug boot off the old module.

2. Remove the spark plug coil spring from the old module.

The end of the spark plug coil spring will have two wires set at 90º angles. The wire ends actually puncture the insulation of the spark plug wire. You will have to pull these ends out of the wire.

3. Remove the ignition wire heat shield from the old module.

This should just slide right off.

4. Using a pair of needle nose pliers, pull the ignition wire out of the old module.

Transfer the module parts to the new module by assembling them in reverse order that you disassembled them from the old module.

5. Install the ignition wire in the new module using needle nose pliers.

6. Slide the protective heat shield over the module wires on the new ignition coil.

7. Install the spark plug coil spring on the new module's spark plug wire.

You will need a pair of needle nose pliers for this step as well. Use the pliers to press the angled ends of the coil into the insulation of the spark plug wire.

Both wires on the coil should be firmly punctured through the insulation in the center of the wire, positioned so that the coil rests at the end of the spark plug wire. 

8. Press the spark plug boot back onto the coil spring.

The new ignition module is not ready for installation into your gas engine.

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#4 Install the New Ignition Coil

You will reinstall your new ignition coil by reattaching it in the same three ways it was attached to the engine to begin with. This is pretty simple, but there's one important detail that can not be overlooked.

The ignition coil is designed to be a very specific distance from the flywheel. This is because the magnetism of the passing magnet on the flywheel must be distanced just right to produce an electrical charge in the ignition coil module. 

You have a couple options for spacing the module the correct distance from the flywheel:

• Use a spacer card. Most manufacturers provide spacer cards for these kinds of repairs like the one pictured below. If you have an official spacer card available, it's the best option for this step.
• If you don't have a manufacturer spacer card, a thick business card can serve as a substitute.

1. Turn the flywheel until the magnet is facing the direction of the ignition module.

2. Prepare the module for reinstallation.

Simply insert the module's fasteners by hand into their original positions before installing the coil.

3. Set the spacer card down on the magnet.

4. Refasten the module to the engine.

Do not completely fasten the module at this point. You'll want a little play left in it so you can make one last double check on its spacing before fully tightening.

5. Reconnect the ignition wires to the engine.

6. Double check spacing and fully tighten the module.

Make sure that the module is resting (not pressed) on the spacer gauge as you fully tighten the fasteners.

7. After the module is fully tightened on the engine, remove the spacer card.

The magnetism of the flywheel magnet will automatically adjust spacing of the module into position even further as the machine operates.

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#5 Reassemble the Trimmer

Again, reassembly will logically follow reverse order of disassembly.

1. Reinstall shrouds and housings.

2. Replace the air filter housing.

3. Replace the spark plug boot on the engine's spark plug.

You're new ignition coil is now completely installed, and your gas powered machine is ready for operation!

Admittedly, this repair has quite a few individual steps, but believe it or not, you can replace a an ignition module in your power tool in under 15 minutes, and at a fraction of the cost of your power tool.

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Conclusion

If your gas powered machine or power tools is having a hard time running and starting, make sure not to overlook your engine's ignition coil as a possible cause.

Visit our Engine Parts Page to get started on your ignition coil repair. You can search by category for your tool's make and model, or you can simply enter your model in the search field at the top of this page.

With these professional repair tips, you're on your way to increasing the value of your equipment again and again.

We strongly recommend that you view this article's video demonstration before beginning your repair:

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What we're about.

The most common mistake that small engine owners make about tune-ups is waiting for the engine to stop working before doing one.

Tune-ups are intended to keep an engine running, not to fix it once it stops. If your engine has stopped working, its possible that the problem could have been prevented with regular tune-ups.

This article explains the steps for a simple 2-cycle engine tune up, including air filter, spark plug, and fuel filter replacement. We use a Shindaiwa T242 Trimmer as a demonstration model for this tune-up, but these steps apply to all 2-cycle engines. 

You will need the following items for this tune-up:

• a ratcheting socket wrench
• a new air filter
  
• a new spark plug
• a new fuel filter
• a hooked wire

Replace the Air Filter

Air filter housings are located in different places on different engines, but they're usually in an accessible area on the outside of the block. In the case of this Shindaiwa trimmer, the air filter housing is located on the side of the engine. 

Your engine's air filter will be visibly dirty when it's ready for a replacement, and like other tune-up maintenance items, it should be replaced at least annually.

To replace the filter, simply remove the air filter housing, take the old air filter out, install the new filter, and then close the housing.

Most air filter housings open and close with a simple screw. 

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Replace the Spark Plug

The engine's spark plug should be replaced next. To replace the spark plug:

• First remove the spark plug boot.
• Use a ratchet to unscrew the old spark plug.
• Install the new spark plug with the same ratchet.
• Replace the spark plug boot.

Replacing a spark plug only costs a few dollars and takes only seconds to do, but the difference in performance will show in your tool's engine right away and throughout its life.

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Replace the Fuel Filter

Replacing a 2-cycle engine fuel filter is the most complicated part of the tune-up, but it is still very easy to do.

The fuel filter is connected to the end of the engine's fuel line which rests at the bottom of the fuel tank. To replace the fuel filter, you will have to fish the fuel line and filter out of the fuel tank.

This where that hooked wire comes in:

• Using the hooked wire, fish the fuel line and fuel filter out of the engine's fuel tank.
• Pull the old fuel filter off of the fuel line.
• Install the new fuel filter by pressing its end into the fuel line.
• Drop the fuel line and filter back into the fuel tank and make sure that it rests at the bottom-center of the tank.

The end of the fuel filter that attaches to the fuel line is barbed. After it is pressed into the end of the fuel line, the barbs help it to stay attached.

The filter needs to rest at the bottom-center of the tank so that fuel can still get to the line when the trimmer is tilted or turned on its side.

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Conclusion

There are a few more things that tool owners can do to tune-up their small engines, but replacing filters and spark plugs are the most important.

Start your 2-cycle engine tune up by entering your tool's model number at the top of this or any eReplacementParts.com website page. The "Search By Model Number" field will take you directly to your tool's parts page where you can get the filters and spark plugs you need.

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What we're about.