Farmall M carb issues

TractorTrev · Dec 15, 2016

Hello to all, I have restored a few farmall tractors and the current one has my number. High compression head but all else is stock. 4in pistons stepped, fresh overhaul, I started with factory settings on the carb adjustment scews and i cant seem to get this one running right. at first I had black exhaust when pulling the throttle and after some more adjusting it is white exhaust when pulling throttle. It seems there is no happy medium. Do i need to file out the jets or??

Janicholson · Dec 15, 2016

White exhaust is an indicator of coolant in the combustion chamber if it hangs in the air and smells sweet. It is cold
right now, and all exhaust makes clouds of steam. Is there misfiring going on, lack of power, stumbling when the hand lever
is pulled back? does it die? Adjustment of the idle richness is the upper carb screw not on the governor tube. power
mixture is the lower front of carb screw. Tell us more. Jim

TractorTrev · Dec 15, 2016

It Idles good but stumbles when throttle is pulled. I got the idle screw set properly it just seems that it will run smooth until the throttle is pulled the garage is heated so the cold is not a factor as to the exhaust. It isnt coolen't but i apreciate that fact as well. I am stumped !!

TractorTrev · Dec 15, 2016

I will keep trying JIm, I may not have the power screw out enough for this engine. She sounds pretty strong. I have yet to put her in gear but cannot wait.

Janicholson · Dec 15, 2016

You are going to get variable white grey smoke till it has 20 hours on it or so. Don't worry about smoke. Another issue is
timing advance. Make sure (timing light at high idle) that it does have full rated advance. Look up the spec. with age
the centrifugal advance springs and pivots wear and rust. Be careful to vent or run it outside. Variable engine speeds and
loads are important. it needs to be out and about. Jim

TractorTrev · Dec 15, 2016

I will put the timing light on it and get her right. Most of my time the problem is that it's only me trying to get these tractors right. An extra set of hands / eyes are priceless when doing this kind of work. Sometimes i get in a hurry just to get to another tractor when I just need to slow down. This one does have a new (NOS 1951) distributor and rebuilt govenor. Next up is 58 minn mo 5 star. Thanks for the insight Jim!

rustyfarmall · Dec 16, 2016

Fuel issues and ignition issues will quite often imitate each other.

Determined · Dec 16, 2016

Like Janicholson said, work it.

Being a fresh overhaul it is going to take some time for the rings to seat, assembly lube, solvents, paint etc to burn off in addition to whatever residue is in the exhaust system.

Break it in then you can do your fine tuning.

Had a piece of equipment brought to the shop years ago that had been through 3 shops trying to address a smoking issue.
One shop even had the heads redone.
Checked the fuel, the feel and smell was not quite right.
Figured someone had mistakenly put some diesel in with the gas.
Drained and refilled the tank, ran it hard for a while and it was like new again.

You can feel around the head and exhaust manifold as it is warming up to get an idea if one cylinder is intermittently fouling when cold.
This can cause it to smoke randomly as well.

Farmall M carb issues

TractorTrev

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Janicholson

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TractorTrev

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TractorTrev

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rustyfarmall

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