Howdy,
I have a JD 180 lawn tractor. Its got a 17hp Kawasaki engine.
Problem is, after my wife hit a bump, the engine will only run in the full
choke position. If you back it down from full choke to fast idle, it
instantly dies, nearly electrical sounding. Prior to the bump, the thing
seemed to run just fine.
Unfortunately, there's nothing electrical anywhere near the lever on the
panel, the throttle plate that translates the throttle cable movement to
carb linkage movement, or the carb itself. Plus if you just move the
linkages at the carb yourself, it does exactly the same thing, so there's
not some electrical thing I'm missing unless its buried in the carb, which
I think is pretty damned unlikely.
All of this made me think that something is plugged up in the carb, so I
pulled the fuel bowl. Looked fine, however in the bottom of the bowl was
an electrical solenoid with a shaft coming out with a seat that looked
like it would (in the out position) prevent fuel flow up the main jet.
So I pulled that out, end engergized it. No change in position. So I
pushed on the shaft a bit and 'snick', it locked back into place. AHA! I
thought, "its letting enough gas by that it runs in the choke position,
but not enough for full airflow!"
So, ever the clever person, I decided that the solenoid was already crap,
so I had nothing to lose. I snipped off the shaft with a pair of side
cutters, assembled everything, and proceded to try and start the engine.
My wife was there of course, and I was ready to be a hero.
Alas, the motor does _exactly_ the same thing.
Damn. Not a hero. Kinda a dupe actually, since I'd said how I thought
I'd solved the problem. :-)
So at this point I'm pretty well confused.
First question... What's the electrical solenoid for? I can only figure
its a safety device, either to stop the motor when you bounce off the seat
with the deck engaged (the owner's manual says the motor should stop
"within a half second" which makes me think it might not just cut the
ignition like how I'd expect it to work), or as a triple safety to prevent
overfilling the carb with fuel (which seems unlikely since there's a fuel
pump and the carb has a float with a seat anyway... Why add a third?).
Second question... What the heck is going on? About all I can figure is
that the carb has a blocked passage somewhere and with the choke "on"
(choke butterfly closed) its either cutting off enough air to get a good
mixture or it also opens another fuel passage. The motor runs pretty well
at a fast idle on full choke too, whereas our other tractor stumbles on
full choke almost as soon as it starts running for real.
Any ideas are appreciated. I hate getting outsmarted by an engine,
particularly a lowly 17hp one.
Thanks!
Mark
|