How to Fix the Starter on a Ryobi Trimmer
Replacing the spring in your trimmer's starter assembly is easy with these professional tips, and it will even save you money on parts.
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.
How to Replace Trimmer Fuel Lines
Grass trimmers commonly need their fuel lines and other system comenents replaced, and this article offers professional repair advice for performing a trimmer fuel line replacement.
Discussion
Discussion for the Ryobi 990r (411088141) String Trimmer
I have a Ryobi 990r which had all of the fuel lines deteriorated and missing. I replaced the fuel lines and connected then to where i felt with no help. I have tried several different routines of the lines that I got off of the Internet with no help. The unit will run shortly at full choke then stalls. Can anyone tell me the correct routing of the fuel lines from the tank to the Primer Bulb. and Carb. Thanks in advance.
My Ryobi 990r 4-cycle string trimmer runs fine, however the trimmer head spins fast even at idle. I've backed off the throttle screw all the way, head still turns. I've been playing with the air fuel mix to reduce the idle speed and the head still turns fast. Could this be a clutch problem? I really need to get the head to stop spinning when I release the throttle trigger, any suggested appreciated.
The fuel system on your trimmer has a filtered inlet that goes to the input tube of the carburetor. The other hose on the carb is the priming hose. It runs from the carb outlet to the input, or suction side, of the primer bulb. The last line runs from the output side of the primer bulb back to the fuel tank. It is the return line.
When you prime your saw the primer pulls filtered fuel into the carb, to the primer bulb and then returns excess back to the tank. To find the suction side of the primer bulb, attach a piece of fuel line to one side of the primer. Now put the line in a small container of fuel. If you see bubbles when you press the bulb, the hose is hooked to the outlet side of the primer. If it sucks fuel into the bulb then you have found the suction side.
Identifying the input and output side of a carb that has a remote priming assembly can be very difficult and there is no rule that applies in every case. Usually you just need to use trial and error on those connections. If you have hooked everything up so you are pulling fuel through the carb, not pushing it into the carb, and your trimmer won't fire, you should just need to swap the lines on the carb and then it should run fine. The important thing is that you have the priming lines setup to pull fuel through the carb.
Weed eater will start and run for 10-15 minutes then will just die. Will restart after several pulls, then runs for another 5-10 minutes then dies again. I've had it in shop and they can't fix it. This is very aggravating. Model # is 990r. Please help!
Try to balance the carb setting and choke. I had same problem with my 990 before I needed my part; it took a while but balanced out in the end. I hope this helps you. --Dave
I am having a big problem locating a dealer who can supply me with the plastic tube/sleeve that goes between the spacer and the retainer wheel on my Ryobi 990r brush cutter/trimmer. I would be very grateful for any information on this matter. Yours, Raymond Differ
I have an 990r gas powered trimmer, 4 cycle engine which is about 10 years old. It will start on full choke but as soon as I move the choke lever it dies. I have put in fresh gas and run stabilizer in the fuel.
The fuel lines on this machine have a tendency to dry out and crack. There's a good possibility that your sucking air into your fuel line somewhere between the tank and the carb.
You may also want to check the carb mount to the engine. Tighten all the fasteners, and see if that helps.
You are correct. It is part #791-181092. It includes both the drive shaft and the housing. The Upper Shaft and Housing is available from http://www.ereplacementparts.com.
I have a model 990R ryobi 4cycle weedeater motor. i have taken it apart far enough to be looking at the clutch assembly and the end of the motorshaft. In the castings on the face of the clutch there is an arrow pointed ccw and the word 'off' above it. Is the output shaft of the motor threaded? /
stuffing the cylinder head full of string is a great idea to keep the engine from turning.....
I don't believe that the output shaft is threaded. There should be a screw in the bottom of the hole on the clutch drum. I haven't worked with this specific model of trimmer much but on all of the other Ryobi trimmers the clutch drum is held on in this way.
I hope this helps!
-Mark
Reply: Clutch Removal
steve66396
Check out ebay item #110907521241. It's an engine I have for sale you can see the shaft where the clutch goes is threaded.
I have an older model 990R , how do you remove the centrifugal clutch??? Do I need to open the oil reserve to keep it from spinning while I turn the clutch?
Removal of the clutch drum isn't too hard of a project at all if you know a few tricks first. The drum is held in place by a screw at the base of the hole on the end of the clutch drum. I believe your model of trimmer will require a Torx #T-25 driver to remove the screw but it could be a hex drive or Phillips as well. The screw will remove with a counter-clockwise rotation. When you try to rotate the screw the engine will likely rotate as well. Here is where a trick comes in. Remove the spark plug from the engine. Now find a piece of small rope, like an old shoe lace. Put the rope down in the hole for the spark plug. Be sure to leave enough of the rope hanging out of the hole so you can remove it later. The rope will bind up the piston so the engine can no longer rotate and now you can easily remove the clutch drum screw.
Good luck with your repair!
-Mark
Reply: Clutch Removal
carl
I have the clutch drum off. am trying to get the clutch off of the motor shaft. Does it just unscrew from the motor shaft?
Reply: Clutch Removal
steve66396
It unscrews off of the shaft. Check out ebay item #110907521241. It's an engine I have for sale you can see the shaft where the clutch goes is threaded.
I have the replacement primer/fuel line. But do not know how to re-pipe it. Have three different fuel lines and do not know where they go. I need advise on installation or diagram.
I had removed the old one before getting the replacement.
I don't see this model listed on your site, but that's what it says on the case. The fuel lines on this 4-cycle trimmer/brushcutter have exceeded their useful life. I tried replacing with generic lines, but they don't fit correctly and leak. The primer bulb has lost enough flexibility that it is probably not going to survive long. Have you parts available to replace these?
I'd still recommend taking a look at the breakdown page to make sure you're getting exactly what you need, but it sounds like those should get you covered.
Hope this helps!
Reply: Ryobi 990r Primer Bulb And Fuel ...
jp2code
Wa-Hoo!
I love forums. This was the part I needed!
I hate reviving old threads, but this is exactly the item I am servicing.
I replaced my fuel lines with standard lines a couple of years ago, and (like the original poster said) they leak like mad!
My bulb just broke as well, so I thought this expensive tool was going to have to be junked.
Is there a general "service kit" for this item?
link removed
Reply: Ryobi 990r Primer Bulb And Fuel ...
Michael
No worries on bringing this old thread back from the dead. The more information we can pack into these things, the better.
The parts I mentioned above should cover everything you need:
The primer bulb assembly includes two fuel lines, but the return line included with it may not be long enough to reach back to your fuel tank. I'd suggest picking up the separate fuel return line just in case.
There's also an OEM Carburetor Repair Kit listed for that tool, which will include things like the internal gaskets, reed valve, diaphragm, needle, filter screen, etc. It won't include the specific items you're asking about, but it's as close as it gets to a general service kit.
By the way, that's a great picture of your trimmer. How would you feel about us featuring it on our 990r breakdown page?
Reply: Ryobi 990r Primer Bulb And Fuel ...
ashton
Gotta love these sites and please keep up the good work! Just ordered my lines for my tank after finding they do not sell the tanks any more.
Reply: Ryobi 990r Primer Bulb And Fuel ...
maniac
i recently changed the fuel line from the tank to the engine. after doing so the motor ran fine for half an hour then stopped suddenly, noticed a gas leak from the bulb which i need to replace but also oil leaking from under the cover over the bulb/carburator. Any ideas what the connection is and what I may need to replace to fix it?
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