Farmall M Surging

[Anonymous-0]

I can't figure out what is wrong with my "M". If it is just setting idling it will surge. However, when I put it under a load it will run great. What do you think is the problem? Is it carb or is it governor? How do I fix it?

 

[Anonymous-0]

My H was kind of acting like that and it turned out to be a loose manifold. Tightened it up and all is fine now. I think the vibration at idle was causeing the exhaust pipe to act like a lever and help open a small gap from the manifold to head gasket, it would surge and then do it again over and over.

 

[Bob M]

Most likely the idle mixture is too lean. Confirm by gradually pulling the choke while the engine is idling. If you find a choke position where the idle smooths out that confirms it.

Possible causes: Idle mixture set too lean (turn the idle needle IN to make it richer); plugged idle mixture circuit (carb needs to be removed/cleaned); loose intake manifold, as Bob Kerr suggests below; leak at the carb to manifold gasket;

 

[Anonymous-0]

It could be your governor is hunting. If it is, you have two options:

(1) Buy it a license and make sure it stays under the bag limit;

(2) Adjust the stop screws, as per instructions in manual. If you don't have a manual, a search ought to pull up the procedure.

 

[Anonymous-0]

There is a spring behind the governor plate that gets weak over time I would replace it before changing any adjustment. If it was fine before then you know the adjustments shouldn't need adjusted. Just food for thought.

 

[Dave from Texas]

Same trouble. Mine had a hole in the intake manifold inside the area with the exhast surrounds the intake. Found it when I knocked off the muffler and looked inside. JB Weld fixed it.

 

[Farmall freak]

After checking the adjustments and changing the Governor spring run the tractor and put loads on the motor. Putting a load on the engine (running in 5th gear is how I did it) cured the surging problem on my M.

 

[Anonymous-0]

my H does exactly what you describe.Don't think it's a spring because it quits acting up for awhile then it'll come back.Because of that I think something is moving around in the carb.Mark

 

[Anonymous-0]

Sounds like too rich one way or another to me. Weather gasket leak, loose manifold, card needs adjusting. Its gas so check the power meter too! I set the power meter to where she dont dog under load (no need to up throttle constantly) and then tweak the mixture. Set it too rich first, it will chug and puff smoke then slooooowly lean it out (turn screw in) till it clears up. I go 1/8 turn then wait few secs till cylinder clear out excess and check again. When its right it will accelerate nice when you throttle it. Too rich it will sputter upon sudden acceleration. Too lean it will pop and backfire or surge.

Thats all providing its not a cracked intake or bad gasket. If its not too bad of a leak you can counter it with mixture screw some.

 

[Anonymous-0]

"Sounds like too rich one way or another to me."

Sorry too lean- and it too early brain isnt working right haha. Thinking about working on my 2500B this morning already must be the tractor addiction kicking in! haha.