Concrete Saw: Hard to Start

The carburetor is designed to mix fuel and air in the proper mixture for combustion. Locate the carburetor underneath the air filter by removing the air cleaner cap. Clean out the carburetor as they can become gummed up over time. You can use carburetor cleaner and a soft brush for the inside. Check that the choke valve is functioning properly. It should be closed to allow the air/fuel mixture to be rich for starting. If it is not functioning properly, it may require a new cable or linkage – depending on the model – and how it is attached (models are set up differently).

The air filter is located on top of the carburetor. Its main function to filter out debris and small participles, preventing it from entering the engine and cause damage to vital, internal engine parts. Over time, the air filter needs to be replaced as it becomes clogged, starving the engine of air and power. This can cause a hard start situation, since the engine cannot breath. Simply, remove the air filer cover by the tabs, or screws, that holds it in place. If the air filter is heavily soiled, it needs to be replaced. You can also wash out the foam pre-filter, or replace that as well.

The fuel filter is located inside the tank and prevents debris from entering the carburetor and engine, causing a clog in the fuel delivery system or internal engine damage. You can remove the fuel filter by using a hook to pull it out of the fuel tank. Inspect to see if it is partially clogged, starving the engine of fuel. On some models, you may have to remove the grommet on the side of the tank and push the fuel line in the tank in order to pull the fuel filter up. Insert a hook in the tank to grab the filter, pulling it out. Clean any debris from the filter. To replace, remove filter by twisting and pulling it gentle off of the fuel line. Replace the filter and reassemble in reverse order.

A muffler decreases the amount of noise emitted by the exhaust of an internal combustion engine. If the muffler becomes plugged, it will restrict the flow of the exhaust leaving the combustion chamber. It will also restrict the amount of air/fuel that enters the combustion chamber. This will cause a hard start situation.
To determine if the muffler is the root of the problem, start by removing the recoil and then the belt cover on the blade side. Loosen the tension on the belt by turning the adjusting bolt counter clockwise until it stops. Disconnect the water line and the bracket by removing the bolt underneath. Walk the belt off the saw blade pulley.
Now, you can remove the blade assembly. Take out the muffler and try to start the engine. If the engine starts, and runs fine, then replace the muffler, or try cleaning it out with carburetor cleaner. Dry it thoroughly with compressed air. If any rust comes out of the muffler, or it makes a noise when shaking, the muffler needs to be replaced. Inspect the muffler for cracks – it will need to replaced if there are.
Install the new muffler. Reassemble the water line and then the blade assembly. Reattach the belt around the blade pulley by walking it back on the pulley. Reapply the tension by turning the adjusting nut clockwise until it stops. Put the belt cover back as well as the recoil.
Readjust your carburetor settings to prevent the engine from running rich, plugging the muffler, causing the same problem to occur. See “carburetor” on how to adjust these settings. Check your carburetor settings and lean out the mixture to prevent this problem from repeatedly happening.

The spark plug ignites the air/fuel mixture inside the combustion chamber. To check the spark plug, remove the spark plug wire from the spark plug by twisting and gently pulling up. Remove the spark plug and check the condition – a normal colour of a spark plug should be a light brown or grey. Clean the plug and re-gap to manufacturer’s specifications. Also, check for any deposit, breakage, melted and corrosion. If you see any of these symptoms, replace with a new plug and gap to manufacturer’s specs.

If the starter is not working properly, for whatever reason, it can make the engine hard to start. See symptom “pull rope has little/no resistance” or “pull rope will not retract” to further diagnose and repair your starter. If you are looking to replace the starter, which is the easiest and quickest to fix, you can simply do that by removing the bolts on the starter and installing a new one. You may, or may not, have to remove a side cover to access the starter on your model.

Ensure you are using fresh fuel and that it is mixed to the proper ratio with your oil for your two-stroke engine. Fuel after 90 days, from leaving the pump, will start to go bad. Bad fuel can cause a hard start situation. If you suspect the fuel has gone bad, replace with fresh fuel.