Farmall M carburetor

m.r.vmax · Mar 11, 2010

Hey guys, I am stumped. My M will run ok until it gets warm and then it starts to spit and pop and backfire until I pull the choke almost fully closed. then it runs fine but when I try to open the choke back to normal it will not run, it sounds like it"s starving for fuel. I have rebuilt the carb and adjusted it for n hour running it wide open and nothing changes. But I can pull the choke and it runs fine sittin still.Any suggestions??

Andrew Z · Mar 11, 2010

sounds like you have debris in your tank, i would pull it off and clean it your self or send it out. Check the bowl as well you could be plugged right there. If you are then i would suggest you get the tank cleaned as well. But really sounds like a fuel starving issue

Andrew

gregk · Mar 11, 2010

sounds like its running lean. Maybe try the needle and seat or more likely something plugging the line such as in the gas tank. If it has a filter check that too. other guys may have better ideas.

m.r.vmax · Mar 11, 2010

The fuel tank was my thought also but I unhooked the fuel line and put it directly on the small kerosene fuel tank and it still does it.

DeltaRed · Mar 11, 2010

you have good fuel flow?all passages are clear?float level OK?sometimes a condenser will do some wierd things.a vacume leak that only appears when warm?An intake valve thst leaks when warm? good luck

Coax · Mar 11, 2010

Don't feel too bad, I completely rebuilt My carb, Installed a very clean 1 gal. Temporary tank,new fuel line and replaced the choke bar w/a aftermarket choke cable. It still starts the same. 3/4 closed, Runs like a champ. Close it or open it any further...Pops sputters and craps out. And to top it off, when it dies fuel starts running out the intake barrel just a little bit then it dries up. But it doesn't leak while it runs...I'm scratching my head too....

jdetig1 · Mar 12, 2010

make sure your valves are set correctly. also make sure it is not sucking any air in where the manifold bolts to the carb, or where the manifold bolts to the head. i had this happen to me once i was really stumped.

DeltaRed · Mar 12, 2010

Coax,sounds like a leaky intake valve. do a compression and/or laekdown test.

m.r.vmax · Mar 12, 2010

I guess it's gonna be a race between us to fix the problem. I have sprayed carb cleaner all around the manifold ad I can't find any leaks but I need to check the compression. I will keep yall posted.

Coax · Mar 12, 2010

(quoted from post at 16:38:20 03/12/10) I guess it's gonna be a race between us to fix the problem. I have sprayed carb cleaner all around the manifold ad I can't find any leaks but I need to check the compression. I will keep yall posted.

ou may be right there, when its popping at its worst I've seen puffs of smoke coming from the middle of the manifold from time to time. I hope I dont find any cracks!!!! And I'll check the valves as soon as the rain slows down...

Farmall M carburetor

m.r.vmax

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Andrew Z

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gregk

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m.r.vmax

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DeltaRed

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Coax

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jdetig1

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DeltaRed

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m.r.vmax

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Coax

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