I bought a Troy Bilt chipper/shredder from a friend; it's got a 5 hp
Tecumseh engine. He bought it, ran it a few times and discovered he really
didn't have that much to be chipped/shredded; he estimates about 12-15 hours
run time, tops. He drained the gas and stored it in his barn, unused, for
about three years. I figured there'd be a little restoration work involved
in getting it running again, although he said it was running fine last time
he used it.
I got it home and sprayed some ether into the carb; it started right up but
ran hesitantly, with light puffs of black smoke coming from the muffler. I
took the carb off, disassembled it, and cleaned off the gum deposits from
all of the surfaces and channels where the gas travels.
On restart, it ran smoothly for a while and chipped some branches. I shut it
down and tried again a little later, at which point it started the puffing
and low power again. I once again disassembled and cleaned the carb but it
wouldn't run strong again. It's obviously getting too much gas, running
rich. When I adjust the needle valve in the float bowl, it runs better as I
tighten it down but it seems like it needs to go another half-turn past full
stop to run right. I did clean the tip of the needle valve so the problem
isn't gum on the point preventing full closure.
The engine has good compression from the resistance to the pull cord and it
has fresh oil in the crankcase. My thought is that there are gum deposits in
the carb in places I can't see or reach; I'm going to put some carb cleaner
in the tank and just let it puff along for a while without load to see if
that cleans it.
Any other suggestions would be appreciated.