Powerbilt 17.5 rpm flucuates constantly

[Beefool]

Hey out there, I'm new to this site and have a problem with a Troy-Built tractor with a B&S Powerbilt 17.5 engine. I loaned the tractor out and it was run for a long time with no air filter. Now the engine is constantly searching. If I stop the butterfly from opening and closing it runs great until I let go. I replaced the seals and the float needle and cleaned a lot of junk out of the carb and it made no difference. Any suggestions would be greatly appreciated.
Thanks a bunch, Bee

 

[Tinkerer200]

Your symptoms are generally caused by one of two things. Governor static setting off or, more likely, fuel starvation. Fuel starvation can be caused by several things from plugged gas tank outlet, crimped or plugged fuel line, leaking gasket between carb & manifold, manifold and head. Usually plugged circuit in carb. though. Water/crap in float bowl will cause it but since you have had that off, would eliminate that.

I can send you a Service Manual for your engine IF you like, address below, put in proper format and remind me what you want and engine model number.

Walt Conner
wconner5 at frontier dot com

 

[Mikel1]

I would clean the carb again. Make sure fuel tank is clean as well.

 

[ILENGINE]

Try applying a small amount of choke and see if it will level out. If it levels out then you need to clean the carb again, but if it tries to flood out, then you have other issues.

 

[Beefool]

Thanks for the tips Guys. I'll open it up again and see what I find.