Adjusting the mixture Farmall Super M Gas Carb

Aaron Bennett · Apr 6, 2009

Can anyone tell me how to adjust the mixture on the Super M carb? It seems my tractor is running rich. I can smooth out the idle, but once moving, it seems to miss and run rich.

Thanks!

old · Apr 6, 2009

How do you know it is running rich?? Does it smoke black smoke??? Any how the main jet is set by opening or closing the lower adjustment screw. A good number of people say to turn it out till you get black smoke then turn it in till the smoke stops. You do that at around 3/4 throttle. That said there are a good number of things that will cause one to miss. Bad plugs, valve set wrong, lean or rich carb, etc.
Hobby farm

CNKS · Apr 6, 2009

PROVIDED your carb is original, the Super M carb main jet is supposed to be adjusted about 3-5 turns out. The 5 turns will be too rich for all but maximum loads. Adjust it out until it does not stumble under load. This is probably about 3-3.5 turns off the seat. If this does not work, your carb needs cleaning. The main jet on the M carb is adjusted in until rough, out until smooth plus maybe 1/4 turn more -- This results in too lean a mixture for a SM carb, and is perhaps the reason some adjust between rich enough to smoke and lean enough to stumble (some call it the "sweet spot" -- I don't do it that way.

Adjusting the mixture Farmall Super M Gas Carb

Aaron Bennett

New User

old

Well-known Member

CNKS

Well-known Member

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