fine tuning 40c

[CELSESSER]

Swampy,
My TSX641 after rebuild idled best at about 1/2 turn off the seat also. It is on a 420 engine. I have to watch mine because the idle screw will work its way out and if it is not idleing well I just have to turn it back in. Who knows how worn the seats are on these things after 50 years of messing with them.

Chuck

[yellowcrawler]

An item to investigate that I experienced.

I had a TSX carburetor on another make of crawler, which I had to run very rich to keep it running. It had a removable venturi that was sucking air internally from the atmospheric vent on the bowl. Took me about a month to figure it out, sealed the venturi with old style Permatex gasket sealer, problem solved!

[Ray III]

Your idle circuit might be blocked up with crap.

(To the original poster)

[Jeff Clark]

I am a new member and just aquired a 40c crawler ,sat for 12 years+ ran bad when it did run, I found the motor frose solid in the cylinders,did a rebuild for the piston condition, but what suprised the old owner was the govener bushings shot and the throttle plate missing one screw and the other loose ,had a croud of doubters but this engine runs great on stock tune settings ,regular gas, 10 year old plug wires ,sounds like something basic wrong.