Farmall M Carb

Garage Dog · Mar 29, 2012

I drug my dads old Farmall M into the garage about a week ago to start working on it. Its been sitting out under a picker for about 15 years which caused the needle to stick in the carb. After a complete rebuild of the Carb 5 years ago it once agin ran but ended up sitting again until about a month ago when i scrapped the picker. After i removed the picker i again rebuilt the carb only to discover that the needle valve wasnt shutting the gas off causing it to flood. I have since installed a new float checked to make sure i was using the proper valve and seat and now it doesn't leak but i cant adjust the idle on the tractor at all i have the idle screw in completely against its seat just to get it to run at all. I would like someone to explain to me exactly what ive done wrong and how to fix it. Two things 1: I had to set the float to 1 9/16" in order to shut off the fuel completely 2: I have no dirt accumulated in the sediment bowl and have purged the line and the throttle body

CNKS · Mar 29, 2012

Take the carb off, disassemble, soak in carb cleaner, blow out with compressed air, put in a IH carb kit, set the float to IH specifications. Works every time.

truckerlary · Mar 29, 2012

Just a thought. Did you get the throttle tang in the
slot when you reassembled the carb to the tube from
the govenor. Larry

Wayne in MN · Mar 29, 2012

Make sure the float pontoons are not rubbing the side of the float bowl.
Take EVERY jet out when cleaning! Use soft copper wire (taillight type) to work through each passage & jet, spray carb cleaner through each passage, and completely blow each passage dry.

JDnTN · Mar 29, 2012

CNKS, please provide those specs for the float and all the needle valves. I agree with an IH/CASE kit. I am working on an M carb now. Even IH kits are not that clear with instructions. Thanks, Jon

pete 23 · Mar 30, 2012

Noticed you said l 9/16 float setting. That is way
off. It should be 1 5/16. The float must lay
parallel to bowl surface. They are tricky to keep
from rubbing on sides of carb. New needle and
seats are often poorly made, however, the ones I
have been getting lately from CASEIH have been the
good looking ones and they work good. I have
coined many seats on the others over the years.
Because I worked on so many carburetors for so
many years I took an old carb bowl, cut the
bottom off and use that for a gauge for adjusting
the float. Did that after I had to run out to a
farmers place to reset a couple after working on
them. The idle mixture screw on an M is an air
bleed, not mixture like a lot of carburetors. So,
if you have to have it all the way in , limiting
the air at idle you are running lean. Low fuel
level, plugged passages, wrong idle jet. Good
luck.

CNKS · Mar 30, 2012

Float 1 5/16" from the bottom of the float to the bottom of the throttle body, that includes the gasket. Main jet 3 turns off the seat, idle mixture 1 turn off the seat. These are only starting figures. Warm up the engine to operating temperature, turn the main screw in until the engine stutters, then out until smooth, plus maybe 1/4 turn more. Lean is better than rich. Do the same to the idle mixture. Repeat both until engine does not stutter when throttle is opened rapidly.

Farmall M Carb

Garage Dog

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CNKS

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truckerlary

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Wayne in MN

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JDnTN

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pete 23

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CNKS

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