Ryobi 825r 4 cycle trimmer quiting at hi throttle

[jwales]

Neighbor dropped it off last week, said it would not run. Dumped the old gas out... along with several pieces of brittle fuel line and filter As long as I was replacing fuel lines I thought I would clean the carb as well. Also discovered overhead valves and re-gapped them. Carb was dirty, replaced the primer bulb but all gaskets seemed to be intact. Starts well and idles good. When I give it throttle it starts to run up but then will quit (bog out). If I play with the throttle a few times I can get it to run WO and it will maintain WO. If I let off the throttle it will go back to idle without killing, but to get to WO again I have to play with the throttle to get there. There are no lo or Hi speed adjustments on this. Any thoughts?? My thought is it isn't getting enough fuel at WO. Any other possibilities? Would the metering lever adjustment be a fix? Thanks

[KE4AVB]

If it was the metering lever it would have problems at idle. If the lever was set too low it would be running too lean at idle or if it was set too high it would be flooding (too rich) at idle.

It should be a Walbro WYL-242 carb if the cross references are correct. If so it should have idle mixture adjustment in the throttle valve assembly. It sounds like it might running a little too lean at idle for proper acceleration from idle. This adjustment also affects the overall fuel mixture. It will be normally plugged with a tamper resistance plastic plug.

You can download the service manual for carburetor from Walbro. http://wem.walbro.com/distributors/servicemanuals/

[jwales]

Aaaaah. I was looking for screws next to "H" and "L" stamped into carb body. Sometimes the view from 10,000 feet is more clear! Thanks for the service manual page. It has "opened my eyes"

[Skywatcher]

Hi J

A customer gave me a Yardworks 4 cycle string trimmer (same basic machine) with similar problems. Replaced fuel lines, primer bulb and carb kit but the machine was always shy on fuel at higher throttle positions. Ended up taking out the main jet and running a #80 (0.0135") drill through the jet. Now the machine runs like a champ and has lots of power for the size of engine. All the best,

Sky