Farmall M

37 chief · Sep 30, 2021

I have a Farmall M. It hasn't run for years. It did run on gas, but would not switch over to diesel. It has been parked ever since. I bought it at an auction. It was loaded on my 54 Chevy flat bed to bring it to it's new home.. It says M on the sheet metal. What's the difference between a Farmall M and a Farmall 400? Can these tractors run for any length of time on just gasoline, without doing harm to the injection pump? Stan

old · Sep 30, 2021

That is not an M but an MD. Starts on gas and then once warmed up switched over to diesel and if you don't know how to switch it over the correct way it will shut down

rustred · Sep 30, 2021

well it could have the wrong decals on it. difference ... basically the sheet metal. it is not the best for them to be running on gas for any amount of time, as those small gas intake valves get hot. just running them probably wont hurt but you cant be driving them around on gas as will be no power just idle. what is the most likely problem is the rack in the pump is stuck and this will not let diesel to the injectors. kind of common when they sit for years not being used. not going to hurt the pump running it. you would need to remove the lines and top cover and side cover to get at the rack to free it up .

used red MN · Oct 1, 2021

A 400 was designed to be equipped with a live PTO and, live hydraulics with integral valving and a Torque Amplifier. On the M & MD or the Super models these items were added on to modernize that tractor line. The 400 did have a little bigger engine than the MD 248 vs 264 CID, but was the same as the Super MD. The x00 series introduced the fast hitch on models over 30hp. I can not tell you if there will be damage to the diesel injection pump if it is run for longer periods on gas, I do not think it will. The thing about it is the gasoline start system is only designed to start the engine and warm it up to switch to diesel. The carb and intake system for the gas side is small and really only designed to run the engine at a fast idle and the tractor will only have minimal power on gasoline. I will attach a link to the tractor data page for the 400 so you can see the physical difference between it and your MD.
Tractordata Farmall 400

redforlife · Oct 1, 2021

The 400 is the same size tractor, just one series newer. They made an MD and a super MD. Make sure thats what you got. An M diesel should have all the injector lines and injector pump and so on. Exhaust coming out of right side of hood. A duel fuel M (kerosene or distillate) are basically built like the gas burners where all the fuel goes through caberator, exhaust comes out left side of hood.
A diesel should run on diesel and only started and pre-heated on gas. A dual fuel burner (kerosene or distillate) can be ran on gas all the time.

Farmall M

37 chief

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old

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rustred

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used red MN

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redforlife

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