Trencher engine running too rich??

[BobReeves]

The Trencher saga continues..

Having a problem with the engine bogging down when the governor is actually giving it the gas. Pulled the plug and it was covered with black soot. I suspect it running way too rich but not sure if I can/should screw with the carb adjustments as I have no idea what I am doing with this old engine.

Have attached a picture of the carb and am wondering if anyone might give me a few pointers on how to be sure it is adjusted correctly.

Thanks,
Bob

 

[J_J]

Several things come to mind. First, a clogged air filter will make the engine run rich. secondly, a stuck choke will do the same thing. Third, the main jet needs to be leaned out.

Recommend new ail filter, lube the choke shaft, and after the first two are done, turn the main jet to the right to lean out the mixture. You may have to reset the idle screw.

The main jet adj screw is on the right of the carb. Once the engine is running, tighten the jet in until rpm's fall off, then back out the jet until the rpm fall off again, Halfway between these two points is where it should be.

The jet setting could be anywhere from one turn out from bottom to about 2 1/2 turns out. If that doesn't work, give that carb a good cleaning.

 

[BobReeves]

Thanks for the response JJ,

The air filter is oil bath is clean, choke is OK also. I can only find one adjustment screw on the carb and was assuming it was the idle mixture but hoping it was the main. Guessing the only way to solve the problem is rebuild the carb. Oh well, just my luck...