Originally Posted by davidmash

I have a 25 yr old craftsman lawn mower. Lately the engine has been giving me some issues.

I pump the primer bulb a few times start it up and it starts fine. Runs for a few seconds at full throttle and then sputters out like it's starved for fuel. It used to be this would happen and after 3 or four tires it would continue to run. Last week it kept dying. I did it about 7 or 8 times with the same result. It has a little throttle control on the side for slow and fast (rabbit and turtle). When I tried putting the throttle on slow, it started up like normal and kept going. I let it warm up a bit and tried fast and it died. Started it up again on slow and started mowing. About 10 min into mowing I put in fast and it stayed running but it seemed like it was surging a bit. When I hit a thick patch of grass, it seemed more susceptible to stalling than normal. I also took the air cleaner off thinking may be it was a air starvation issue but having the air cleaner off had no effect.

I figured may be the carb needs to be cleaned out but I have never done this before on a car much less a mower. Does this sound like a carb issue? Something else? Should I get carb cleaner or can I use brake cleaner or paint thinner to clean it?

Thanks