Farmall M vibration just off idle

Schultz · Mar 12, 2014

You guys ever had a Farmall M with a vibration? Mine vibrates bad just off of idle. Gets better with rpm. Rebuilt engine with oversized pistons and I put a 12" flywheel/clutch on it.
Seems like fueling or spark at that point but slewed both at that point and no difference. Also running a Pertronix.

Any ideas?

Thanks,

rustyfarmall · Mar 12, 2014

(quoted from post at 06:50:11 03/12/14) You guys ever had a Farmall M with a vibration? Mine vibrates bad just off of idle. Gets better with rpm. Rebuilt engine with oversized pistons and I put a 12" flywheel/clutch on it.
Seems like fueling or spark at that point but slewed both at that point and no difference. Also running a Pertronix.

Any ideas?

Thanks,

Vibration? As in making the sheet metal rattle? Or something that you can feel, but not hear?

gab · Mar 12, 2014

Don't know how normal it is but we had two strong running M's when I was a kid and I remember the draw bar pins would dance and rattle at a certain speed in one or maybe both of them.

Schultz · Mar 12, 2014

Just feel, sheet metal rattle, steering wheel & fuel tank shake. Sounds great. Runs fine. Just don't want to break something.

Bob M · Mar 12, 2014

My Super M vibrates the steering shaft/wheel with RPM just off idle. A bit faster the steering wheel stops vibrating but a drawpin loose in the drawbar will now dance. Faster than that and everything settles down. It's been like this the 40+ years I've owned the tractor - I presume this is "normal".

Keep in mind also the M crankshaft is not counterbalanced so the engine's bound to vibrate some. Now add your oversize (heavier) pistons and vibration is bound to increase.

As long as your M runs OK otherwise, I'd not be too concerned.

Janicholson · Mar 12, 2014

They are an unbalanced engine (two pistons up two down that keeps it from taking out your fillings) they do vibrate with zero rubber engine mounts and unless it is much different than before you put in the clutch, it is probably normal. After a day of operation your whole body will tingle for an hour or so. If it is way different, you might have gotten something in the clutch cover that threw it out of balance. Jim

metalmender · Mar 12, 2014

mine did the same exact thing, a little detective work revealed a cracked fan by the 4 mounting bolts

notjustair · Mar 12, 2014

Mine does the same. It vibrates less at full throttle grinding corn than it does just off low idle. The drawbar dance must be common. If she runs good just turn up the radio.

Anonymous-0 · Mar 12, 2014

My Super M has done the same thing and we've had it all my life. When I restored it I rebuilt the engine and it still does the same thing so I just wrapped a rag around the drawbar to keep the noise down. Good enough for me.

Ellis Kinney · Mar 13, 2014

My M does the same thing. After an hours work, when idling it down prior to shut off, it goes through a vibration just before idle. When it reaches lowest idle the vibration quits. I have owned it over 40 years and 2 overhauls and consider this to be normal for this tractor. Ellis

Farmall M vibration just off idle

Schultz

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rustyfarmall

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gab

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Schultz

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Bob M

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Janicholson

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metalmender

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notjustair

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Anonymous-0

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Ellis Kinney

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