How to Replace a Primer Bulb
Replacing primer bulbs in small engines is one of the most common types of tool repairs, and this article explains professional steps for primer bulb replacement in two engine design types.
I can see two different styles of tanks. Take a look at this parts diagram 790R 41AD790A734 page B, and look how item number 30, starter housing is connected to the fuel tank. Then look at 790R 41BD790A034 page B, and see how the item number 34, starter housing fits around the fuel tank and half of the fuel spout. Hopefully this will help you figure out which one you will need.
THE PULL CORD SOMETIMES ACTS LIKE IT DOESN'T 'CATCH". IT CATCHES PART TIIME AND IT SEEMS NORMAL BUT NOT ENOUGH TO CRANK IT. WATCHED THE VIDEO ON THE CLUTCH ASSEMBLY AND IT TECHNIQUE WORKED GREAT, THANKS mARK, DID NOT SEE ANYTHING WORN OR BROKEN BUT HE PULL CORD WAS WRAPPED ONCE AROUND THE SHAFT SO i PUT IT BACK TOGETHER HOPING FOR THE BEST. NOT SO LUCKY. WHEN IT CATCHES, THE COMPRESSION SEEMS GOOD, THE CORD RETRACTS LIKE IT SHOULD. FYI,THE CLUCTCH PLATE IN HIS MODEL IS ONE PIECE WITH A SPRING AROUND THE PERIPHERY OF IT. WHERE SHOULD I LOOK, THAQNKS. ENJOY YOUR VIDEOS!
I can see two different styles of tanks like you are saying. Take a look at this parts diagram 790R (41AD790A734) page B, and look how item number 30, starter housing is connected to the fuel tank. Then look at 790R (41BD790A034) page B, and see how the item number 34, starter housing fits around the fuel tank and half of the fuel spout. Hopefully this will help you figure out which one you will need.
The drive shaft on my Ryobi 790r is not engaging the click on attachments. I dissasembled the upper shaft from the motor assembly and found a broken spring, part #
791612468. I am going to order this part and see if this solves the problem.
i ordered an upper drive shaft for my trimmer and it came in a metal tube. Is this tube for shipping or do i remove the drive shaft and install it into the tube already on my trimmer? also, what kind of lube/grease do i need to use on the drive shaft?
I recently ordered a replacement upper drive shaft for my ryobi 790r trimmer. I received it in a metal tube similar to the tube the drive shaft goes in on my trimmer. Is this a replacement tube or do i remove the drive shaft and instal it in the tube already in place on my trimmer? Also, what kind of lube/grease do i need to use on the drive shaft(s)?
cannot remove the outer spool eyelet of the bump head assy from the shaft. Tried pulling, tapping, wd 40 cannot get it to budge, Any ideas? could it have become fused? I did remove the retainer ring so i assume it should pop off, thanks, ARTIE
So why doesn't the parts breakdown show figure 17 on the 41FD790A034? I've looked at all other similar Ryobi models and no matter which figure that part is labeled, it is always omitted on the breakdown. This bracket assy keeps the trimmer head straight and allows you to loosen up to pivot the directionally. It is directly between the lower and upper shafts where the big screw knob goes. Can I get any help?
The tank leaks around the lines because the lines have become hard and brittle with age. The lines form their own seal where they pass through the tank. As they age and become hard they no longer make a good seal and begin to leak. They will need to be replaced. In this case you will need to replace the tank assembly. Ryobi offers many of their tanks as assemblies with the lines already in them due to the difficulty in replacing the lines only.
I have 2 Ryobi EZ Trimmers (Model 790r and 725r) neither of which have a Model Number that starts with "41" (Example: 41AD790A734). I do have SN & PNN Numbers, and Year of Manufacture...and a Barcode.
So, is there a way to Cross Reference the Existing Sticker Numbers to the "41" Numbers?? :confused:
Here are the Numbers on the Stickers, hope these can be cross-referenced?
[FONT="Comic Sans MS][COLOR="red]Mdl: 725r EZ
Mdl: 790r EZ
My girlfriend has a good working Ryobi 700r.
I recently found a 790r (same cc engine, but has a straight shaft) trimmer sitting at a curb with a "free"sign on it. Engine probably doesn't work, but I figured I could use it for spare parts for her 700r.
Then I thought why not put the straight shaft on her curved Ryobi?
Is this doable, and is it as easy as unbolting the housings and swapping them?
I've rebuilt the carb on her 700r, and I'm a decent backyard mechanic, but I admit I've never messed with the shaft/gear part of these trimmers, so any help is appreciated.
The part number 791-613300 is the lower drive shaft only. If you need the upper drive shaft also, you will need part number 753-04344 upper drive shaft and housing assembly. Make sure you order off of the correct parts diagram by the model number of your trimmer, it will start with a (41---------).
You should be able to see a white label with a bar code on it. There will be a number starting with 41------ That is the actual model number of that unit. Match that number to the parts diagram and you will be able to find the parts you need.
If you can let me know the part you are looking for I will see what I can find for you. If you look at the breakdowns on the various series of that model number there are parts that do interchange. But let me know what you need and we will try to locate it for you.
Did some major digging and here's what I found about the Ryobi 825R trimmer:
* Engine is 793-00007 aka AC-2.1, 26.1cc
* Fuel Line 0.080 ID, same as poulan 530069247. Tygon is better.
* Carburetor is Walbro WYL-187-1 aka Ryobi/Ryan/MTD 753-1225
* Carb Diaphragm kit is D11-WYL
* Carb Metering spring is 98-3160-7
* Carb Rebuild is K20-WYL or Ryobi 753-04014.
* Primer Bulb is 188-16-1 (originally 188-12-1)
I have a 790r trimmer. The fuel line holes in the tank are different sizes. I picked up fuel line and return line from local small engine repair shop. They said the holes should be the same. They aren't and I cannot get the purchased return line through the hole. The return line #791-683976. This is not the correct number according to manual and your site but the local guy swears it is correct.
The return line is slightly smaller, but that's because there is nothing but the line itself that holds in place. I found if you cut the tip on a 45 degree angle, it's a little easier to get it in the hole. The feed line has the filter assembly that holds it in place and has to fit into it. Hope that helps.
You will need to remove the clutch drum. Removal of the clutch drum isn't too hard of a project at all if you know a few tricks first. We have prepared an article and video that will provide you with all of the information you will need to remove the clutch drum. You can find the article and video at the following link...
I recently was given a Ryobi 790r split shaft trimmer. There is apparently something missing where the 2 shafts join together to allow the upper and lower drive shafts to engage. Trimmer runs great, upper drive shaft rotates, but there is nothing there to allow the lower shaft to engage. I see nothing on any of the parts diagrams. Is this a replaceable part or do I need to replace either the upper or lower drive shaft housing?
I am going to guess that the damage is to the upper drive shaft. The upper shaft should have a fitting with a square hole in it that will accept the lower shaft. The fitting is somewhat conical on the top and then tapers down to the square hole in the center. The conical portion helps to guide the two shafts together. I suspect that the fitting has broken off.
The drive shaft is part of the Upper Drive Shaft & Housing Assembly. It is part #753-04344 and is available from http://www.ereplacementparts.com.
I replaced the orig bump head with an all-in-one assembly, where you have to restring the spool rather than replace the spool cartridge.
Is there a bump head assembly where in the future I can replace just the cartridge?
Most of the fuel line used on the Ryobi trimmers is metric sizes. The line at the local hardware store is very likely a SAE size. Your best bet is to replace the lines with the Ryobi parts. You will need to order three parts to get all of the needed lines. The Fuel Return Line is part #791-181086, the Fuel Line Assembly is part #791-682039 and the Primer & Hose Assembly is part #791-683974B. All of these parts are available from http://www.ereplacementparts.com.
The version number or as we call it the "barcode" number is located on a barcode sticker somewhere on the tool. It is not uncommon to find it on the underside of one of the plastic housings. Many times you need to remove the housings to locate the barcode number.
Hey Robert! Yep carburetor #791-182875 will fit your particular model. Don't forget to install new fuel lines #791-682039 and a fresh fuel filter before installing your new carburetor so debris and anything else doesn't get in your new carburetor and gum up the diaphragm! The fuel lines in the above mentioned part number includes the fuel filter. Also from experience don't forget to take your muffler off and clean out the spark arrestor screen! After time these become clogged and make the engine very hard to start!
Hope this could shed a little light on your problem!
Best of luck
Unfortunately the manufacture does not offer a carb kit for your trimmer. You can replace the carburetor to make your repair. You will need the "bar code" number off of the tool to get the correct carburetor. This number is usually hidden on the underside of one of the plastic housings. It is the number that Ryobi uses to code any changes that may have been made to a tool. It will start with the number 41. Once you have that number you can look up the proper carburetor.
My Ryobi # 790r will not run it is hard to start, then it will run only a few minutes and stop.
It seems like it is not getting and fire. Your part list do no show all engine parts.
Sounds like classic dirty carburetor problems. Replacing the carb should get you running again. It is part #791-182875. The majority of carburetor issues are caused by fuel being left in the tool when it isn't used for extended periods of time, such as over the winter. Whenever gas powered tools are going to sit idle for more than two or three months you will want to get all of the gas out of them. When gas sits inside of the carburetor it will varnish inside the carb and cause it to become clogged.
The diagram (790r) shows connections at the fuel tank but it doesn't show where the fuel line and return line connect at the opposite end. Can someone provide clear instructions/diagrams for installing the fuel and return lines?
I just rebuilt the zema carb on my 791r--
My fuel lines went as follows:
The line connected to the tank filter, attached to the bottom carb. connection
The line simply stuck in the tank went to the upper primer connection.
The lower primer connection attaches to the upper carb. connection.
I have 2 Ryobi Weedeaters. Models 725r and 790r. I have looked for the numbers that match with the numbers listed on the parts breakdown. My 725r was bought as a reconditioned unit, and does not have any identifying labels. My 790r has a label on it that has the following information:
MOD 790R BLKDF
S/N 401009944 PPN500792
It also has 2 wing screws on the part that connects any accessories. I have looked at all of the part breakdowns and none of them has the same part.
Where can I find a parts breakdown for these units?
When I try to pull the cord to start my 790r trimmer, the recoil assembly is jammed. I have run into a problem trying to access it and that is that I cannot get the clutch drum assembly off. It seems that I would need to get past this assembly to see what the problem is with the recoil assembly. any tips would be greatly appreciated.
My 790r is about 6 year old and has run great until now. It's spraying gasoline all over the place. I looked at it and the gas line that has a union on it has cracked and broke in half from use. I tried cutting off a piece and then placing the freshly cut end over the union, but it isn't holding well enough for me to feel good about it. I need to replace it.
It appears to be the line going from the carb to the gas tank. How to I physically replace it and where can I find one? Should I go ahead and replace the other lines -- what do I need and how do I replace those?
Replacement is really pretty simple. The main thing is to take note of where all of the lines go before you remove them. The new lines will thread back through the holes in the fuel tank and make their own seal as they do so. The connections on the primer bulb and carburetor are simple push on connections. I don't think you will have any problem with the installation at all.
I have a Ryobi 790r trimmer it has two fuel lines running to the carb one is the inlet & the other is the return one is on the top of the carb the other is at the bottom.
What I need to know is which one the top or bottom goes to the primmer bulb & which one goes to the fuel tank?.
this seems to match the drawing that does not show a fuel tank nipple for the return line. There seems to be no correlation between the serial number on the tool versus the model numbers' parts lists on this site.
So, does the correct kind of fuel line fit so well in the hole in the fuel tank that gasoline won't leak around it?
trying to replace pull rope on trimmer model 790...have taken off top but do not know how to get clutch off..any advice will be appreciated..does this clutch have a screw on the end
of shaft holding it on?
Hi ned! Yeah those can be a pain in the you know what sometimes! But with a little patience you can nail it! After you have taken the top off you will see the clutch drum assembly. In order to disassemble it you will need a old piece of rope and a phillips screw driver.
Here's what you want to do: take the spark plug out and make sure the piston is all the way down, feed the rope into the spark plug hole until you can't feed any more in. This keeps the motor from turning so you can take out the screw at the end of the shaft.
Then you take your screwdriver and insert it into the end of the shaft and start unscrewing the screw in a counterclockwise position and before you know it the clutch drum is off! To remove the clutch itself keep the rope in the combustion chamber and take a pair of channel locks and turn it in a counterclockwise rotation. It might take a little oomph, but it will come off!
Since you're already there, I'd recommend replacing the clutch assembly and drum while you're at it. That way you don't have to take it all apart again a few months down the road when you realize the clutch is starting to wear out as well!
After you have removed the drum and the clutch you should be able to get to the starter assembly. I have included a link to a video that should help you give you an idea on how this is done. You can purchase all the parts you need from www.ereplacementparts.com. Take extra care when ordering to have the exact model number handy when you're ready to order.
Here is the link to the video, this is NOT your exact Ryobi trimmer, but it is an excellent reference video to give you an idea of how this is going to come apart! link removed
I have a Ryobi 790r trimmer that has been sitting in my barn for two years without running. So I figure today I would take it apart & do some maintenance on her but I was looking at the diffrent 790r numbers & can't find mine.
Maybe this is not the right number what I found was 40A6987 I believe I bought this in 2000 but not sure.
I guess my question is if this is not the number (as I did not see it on the parts page) where do I find the right number? so I can order the parts.
I recently ordered part 791-180804 for a Ryobi 790r brushtrimmer. Although none of
the samples given matched exactly my SN or Engine SN I still ordered. Upon receiving
I noticed a few differences. One was the orginial housing had a spacer that fit in the head
of the unit..this housing can not use it?, but fits snuggly without it. But my real problem is it appears the housing is about 1" too long? I can not get the drive shaft assemble to fit in the upper housing?? it seems to be about 1" too short to make the connection?
My sn is 505029487 ppn 501014 engine family number is sn40314824ra