farmall M carb adjusting

johndeeregreg · May 18, 2017

trying to get my M so it will run smooth, at low idle it runs smooth and just whispers along but when i open it up to high idle it surges like its switching between the idle and load circuits. i try adjusting the idle screw (the one by throttle shaft that's at an angle) with it running wide open and think i get it running a little smother for a second or two then it goes right back to its surging. I'm not sure where i have the idle or load needles as fare as turns open goes. i have had the carb off at least twice and went through it and both times i thought i had all the passages cleaned out. what am i missing? i have been through the governor adjustments using the I T manual so i'm pretty sure i have all that adjusted right just seems like my issue is with the carb to me.

will an M run as smooth as an H or super H? my neighbor has both and they run really smooth compared to my M

Janicholson · May 18, 2017

If the surging is accompanied by black smoke, the load screw (Pointing front bottom of bowl) is too far out. Try 4.5 turns. If no smoke, it may be too lean. Turn it out some. If the screw makes no difference there is an plugged passage in the high seed circuit. Carb dip, and run wires through each passage or bleed hole. Make sure the float level is set correctly. Jim

johndeeregreg · May 18, 2017

i cant say it really smokes a much, a little when i open it up wide open from idle. just that once it gets wide open it surges. i can remove the idle screw and it doesn't change any thing while wide open.

John M · May 19, 2017

Start it up and let it warm up. At idle, turn the idle mixture in or out, looking at the exhaust pipe, and adjust until it stops smoking. (The way I do it anyways.) Fast idle is 1 to 5 turns out. After 5 turns out, you arent really doing anything, since thats max flow. It does sound to me like like a governor problem with the surging, though, but it could just be a dirty jet, or passageway.

johndeeregreg · May 19, 2017

should add that once the tractor is under a load wide open it seems to smooth out and pull just when there isn't any load or a light load that it surges. so what should i look at or adjust in my governor? does a farmall repair manual have some more information that the I T manual maybe doesn't that would affect this?

rustyfarmall · May 19, 2017

Might not be the carburetor. Might be the distributor is worn out, or maybe the timing is too far advanced. Start the engine, let it warm up a bit, then pull the throttle back to wide open. Slowly rotate the distributor one direction, and then the other until the engine runs smooth.

John M · May 19, 2017

That does sound like the governer to me. Pull the side cover off and check that spring. The holes the spring hooks to is probably wore.

johndeeregreg · May 20, 2017

just messed with the M a little bit this morning. i adjusted the timing, turned top of distributor out towards me a couple degrees, it helped. if i bring throttle up slowly it will run smooth but if i open it up quickly then it just surges non stop. i had the cover off governor and if i steadied the arm right by the cover it would hold steady on its own till the load changes then back to surging. i have a governor setting on the shelf that came off the original engine that was seized up, i wonder if i should clean that one up and switch them out and see if that one is better?

after messing with it today i don't think the carb is the issue

johndeeregreg · May 20, 2017

i just switched the governors and made a few adjustments and now it runs great, pull throttle wide open and it just winds up to where it should be and stays there, haven't taken tractor out of shed as its blocked in and raining but initial indications say that it is pretty responsive.

i kind of wonder if i didn't have the other governor synced with the carb, the book i have says the pin where it makes the 90 degree turn to the carb should slide in freely with everything in wide open position, how ever when i got done adjusting the governor i just put on i had to move throttle lever to a slower position to get the pin in, which makes sense i don't think i have had a governor to carb linkage on anything that was suppose to just slide together.

as much as i would like to know if that was my issue, I'm not going to put that other governor on and try adjusting it more to see if that was the problem, now that i have this one set right that's how it will stay.

farmall M carb adjusting

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