Farmall M has poor power

ldj · Jun 4, 2011

Just got this after setting 3 years. Cleaned gas tank, carb, and mag. Tractor doesn't miss and runs real smoth The mag is fires with battery and 12v coil. After warmed up to temp. set valves to .017. It is so low on power it won't take off in road gear. On the carb., where the main gas screw seats inside the carb. bowl into a little tube, that little tube is cracked. The tractor doesn't run rich enough to puff out black smoke. I would think that crack would make it run very very rich. I wouldn't think that crack would make it have low power, especially since it isn't puffing black smoke.

Also I think it isn't turning RPM it should. I don't have a tech. so not sure about RPM. However it turns fast enough I would think it should take off in road gear.

Anyone have any ideal about the gutless low power? Carb.?, low RPM? or what might I try?

Allan in NE · Jun 4, 2011

It's a M for goodness sake.

Of course it's not gonna take off in road gear; it's just too steep of a gear.

Allan

El Toro · Jun 4, 2011

That main jet adjusting screw is where you enrich the fuel mixture by opening it . Garden tractors use that same feature. I would replace that tube and soak that carburetor in carb cleaner and blow out all the jets with air. Your road gear is probably too high to take off in it. Try a lower gear to get it rolling then shift into the road gear. Hal

gold1456 · Jun 4, 2011

My m wont take off in 5th gear they just dont have the power.

CNKS · Jun 4, 2011

5th is not a gear, it is a splined shaft, it is direct drive. 5th has no gear reduction, yours is like all other M's.

ldj · Jun 4, 2011

OK I never drove an M. Other tractors I have drove with road gear would start in road gear. Now sometime when you start it, it will backfire. After moving once in a while it will cough back through carb. That makes me feel better that a M needs to start in 4th.

55 50 Ron · Jun 4, 2011

"mag is fires with battery and 12 V coil" If you have a mag you don"t need a coil. So what DO you have? An "M" was originally 6 V. Is this a 12 V change over? If you really have a 12 V coil and the battery is still 6 V, that could be your problem.

Also an "M" will start in 5th gear if you "feather" the clutch a time or two, that is if the engine is working correctly. I"ve done it many times, although starting in 4th and shifting to 5th after it"s rolling a little will be the best way to do it.

They are indeed a sweet tractor!

John M · Jun 4, 2011

All 3 of my Ms will take off in 5th from a dead stand still. Takes an easy foot on thecltuch, and throttle, but all three of mine will will do it. Easier to go from a roll, but it can be done.....

CenTex Farmall · Jun 4, 2011

My well worn "50 M will start in 5th with a little foot work.

Have you checked the timing? Be sure that the advance mechanism is operating properly as I"ve found them stuck. The timing could be retarded.

ldj · Jun 4, 2011

55 50 Ron,
It is a mag that isn't good. That is the reason I call it a mag. The points and condenser in the mag are used to fire a 12v coil and the tractor has a 12v system.

NDS · Jun 5, 2011

After starting M off in 5th gear hundeds if not thousands of times I know it can easily be done on flat hard surface. Ms with cotton pickers mounted are carrying 3 to 4 K load and will start off in 5th with no problem. You do have to know how to use clutch without excess slipping.

Allan in NE · Jun 5, 2011

Why would anyone intentionally burn the clutch to start off in 5th?

That doesn't even qualify as semi-sound reasoning.

Allan

John M · Jun 5, 2011

I havent repalced a clutch yet. (Keyword yet) You allwere saying iot cant be done, we were saying it can be! If ya cant do it without burning up a clutch, you aint been driving an M as much as others have.

55 50 Ron · Jun 5, 2011

Now I'm really confused!! Why do you need a 12 V coil? A mag doesn't need a coil.

NDS · Jun 5, 2011

We never had clutch troubles on 2000 hr/yr tractors but I have seen 5th gear ground out of a lot of them. Yep someone that pulls throttle all the way back and slips clutch to get started will have clutch problems but someone that can use clutch properly will not. Just set throttle about half way bump it with clutck to slightly move it depress cluth and let it all the way out as you open theottle.

Janicholson · Jun 5, 2011

In my opinion the fact that it has a repurposed mag is a part of the problem.
If the mag impulse coupling is bad, and does not click, the timing has probably been set so it will start. Mags have only impulse start timing at TDC, or full advance.
If it is being spun to start with a 12 volt it might spin too fast for the impulse to work.
Replace the bad mag with a distributor and you will find power (my opinion)
THey will start out in 5th, but why torture the clutch. Fourth to 5th shifting is SOP. Do it modestly and it only grinds a little. Throttle down and double clutch between wide open 4th and idle 5th and it doesn't grind. Takes 4 hands though. Jim

rustyfarmall · Jun 5, 2011

(quoted from post at 11:36:00 06/05/11) Now I'm really confused!! Why do you need a 12 V coil? A mag doesn't need a coil.

The coil inside the mag is no good. Instead of replacing it, someone just bypassed it with an external, battery powered type coil just like a full fledged battery ignition distributor uses. It is a shortcut taken by some folks who don't want to spend the extra $30 or less to do the job right.

NDS · Jun 5, 2011

Out of curosity I looked up start instructions in official IH operators manual for M. "Disengage clutch by pressing clutch pedal all the way in. Hold clutch pedal in this position and move gearshift to desired speed. Start the tractor in motion by slowly releasing the clutch pedal. NOTE: Do not shift gears while engine clutch is engaged or when tractor is in motion.

55 50 Ron · Jun 5, 2011

5th gear starting is an interesting topic with lots of disagreement. There is probably no one correct way to do it. I don't believe it puts any more wear on the clutch than any other use of the clutch.

Allan in NE · Jun 6, 2011

Com'on now,

2000 hours a year? This story is getting taller as we go. :>)

Allan

Allan in NE · Jun 6, 2011

And you do realize of course, that the manual was completely finished and in print long, long before the first issue of that particular tractor was even sold?

That's why reading out of a book and operating in the real world will very seldom "jive". :>)

Allan

NDS · Jun 6, 2011

Allen you are entitled to your opinion of course but I will bet that I have at least as many hours on Hs and Ms as you do and have been starting them off in 5th gear for over 60 years without any clutch problems but it my catch me yet.

NDS · Jun 6, 2011

Allen that is estimate of course as tractors had no hour meters but after we got tractors with hour meter we would run 1200 to 1500 hours/year and we did not have to run them near as hard as we did Hs and Ms to get crop made as they were about twice the horsepower.

Farmall M has poor power

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