Anybody know anything about small engines? (I know, silly question to
ask on this list!) Specifically, a two year old Lawnboy 2-stroke (it's
always had the proper gas/oil mixture). Last fall it was starting to
run a little badly and the engine speed was starting to fluctuate. I
figured I'd wait till spring and clean the carb and that would be that.
Well, Saturday I took the carb all apart and cleaned it inside and out
(mostly out, because the inside was very clean already). The main
(only) jet was not clogged at all. I put it all back together and
cleaned and oiled the air filter. When I started it up it seemed to run
perfectly (no missing or coughing) but the speed continuously goes up
There is what I guess would be called a governor, which is composed of a
blade that sticks up into the air flow of the fan on the top of the
engine. This blade is attached to a butterfly plate at the end of the
carb that mates to the engine. The faster the engine runs, the more the
air pressure pushes the blade in a direction that closes the butterfly.
There is also a coil spring around the shaft at the base of the blade
which tries to push the blade in the opposite direction of the air
pressure. I think the manufacturers intention is for the spring and air
pressure to find a balance and produce a steady running speed.
My question is, why can't my mower find a steady speed to run at? The
governor blade is continuously moving back and forth, and thus the rpm's
go up and down. If I adjust the spring a little tighter, the rpm's go
too high and won't come down until the throttle is closed almost all the
way. If I adjust the spring looser to where the rpm's level out, the
top speed is way too slow.
I know this is probably something simple, and the repair shops around
here are backed up for a couple weeks. Can anyone help me out?
(Great with cars and motorcycles - just can't understand mower and