Gas vs Deisel

Tom R.S. · May 12, 2010

I saw a post in the For Sale section for a Farmall MD. The guy said it runs good on deisel. Then he said he has not tryed it on gas yet.
WHOA!
Am I missing something?
I never heard of a deisel engine being run on gas and frankly always thought this would ruin it - like now!!!!
Can you run it on gas?

spacechem · May 12, 2010

In the days before we had powerful electric starting systems, it was not unusual to start a diesel engine on gasoline with lowered compression and, when temperature started to rise a bit, you threw a lever to raise the compression and switched to diesel. It was never advisable to run them for prolonged periods on gasoline.

The alternative was to use an auxiliary gasoline engine to spin over the diesel ala John Deere and Caterpillar.

Maybe the For Sale poster has found a way he can get it started directly on diesel. Maybe he’s confused like you. Maybe he parks it on a hill…

Athol Carr · May 12, 2010

Furthermore, on gasoline you had no governor control, the engine was set to run at about 800 rpm, there were no driver controls on the carburettor. Once you switched over to diesel then you had governor control. This was the IH way of starting diesels beginning with the WD-40 in 1934. The German IH had diesel version of the F-12 with a 3.35"x4" (132 cub inch) engine with glow plugs in about 1950. This later became the engine in the German IH Farmall DF-25. IH UK had a diesel version of the Super M engine BD-264 with glow-plug starting about six months later.

MarkB_MI · May 12, 2010

Many of the older International diesels started on gasoline. There was a separate intake manifold with a carburetor on the engine, and a third valve in the head that opened to lower the compression ratio. They were easily started on gas, in fact you could-hand crank them if necessary. Once running, you switched over to diesel.

I've never heard of anyone starting on diesel, although I suppose it's possible if you have a good battery and starter. Maybe he meant to say it runs OK on gasoline.

Anonymous-0 · May 12, 2010

Probably pull starts it...lotsa John Deere dsls w/ inoperative pony motors been workin for years by being pull started...could do the same with an MD...alot cheaper than repairing a pony motor...probably not so expensive to fix the gas side of a Farmall...some people are just a lil afeared of it as they have never been into one.
Tons of British dsl tractors of all types of starting that plain old won't/don't start unless they are pulled workin' also!

Tramway Guy · May 12, 2010

Almost all of the U.S. made IH Diesels for Farm use started on Gasoline, ran on gasoline to warm up, then switched to Diesel operation. A third valve in the Cylinder head opened to lower the compression ratio and expose a spark plug chamber in the head. This design was used through the model 450 Diesel. When the 60 series came out, all that ended.
Many of the IH crawlers had the same type of engine, in four and six cylinder versions.
Yes, they could be started directly on Diesel when warm, but you needed a strong battery.

Nancy Howell · May 12, 2010

Pull starting a tractor is very hard on the clutch. Folks we bought our JD 70 diesel from learned that the hard way. They never wanted to mess with starting the tractor using the pony motor and just pull started it. Tore the clutch up and they had to rebuild it.

Eldon (WA) · May 12, 2010

I don't see how pull starting can be hard on the clutch....it was designed to handle the engine hp and pull starting it doesn't even begin to take that much hp. I'd rather believe the clutch wasn't properly adjusted since the previous owners were too lazy to fix the pony motor....

Nancy Howell · May 12, 2010

I'm not a mechanic, so I can't speak from personal knowledge or give specifics. My statement that pull starting a tractor is hard on the clutch is based on what we have been told by two very experienced JD vintage tractor mechanics.

old art · May 12, 2010

pull starting an engine you put the transmisiom in its highest gear like 4th or 5th for the easy of turning the engine over slowly not 1st or 2nd witch turns the engine over fast when being towed. if you dont believe try it both ways and see for your self . old art

Tramway Guy · May 12, 2010

Perhaps the damage was done when they pulled it so fast in too low a gear; that would tend to overspeed the clutch plates and they might disintegrate....I have seen it happen.

Mike (WA) · May 12, 2010

Usually, the gear selection is "self-limiting"- too low a gear, and rear wheel will just skid and not turn over. High gear is best, and even then, you need hard packed road- and you better be quick on the clutch when it catches!

Anonymous-0 · May 12, 2010

I can see how it would be hard on the clutch if the clutch was pushed in to get the tractor up to speed and then the clutch was "popped" very fast. I think it's best to put the tractor in gear and not even touch the clutch if you don't have to. If not slowly let the clutch out while still going fairly slow, the same as if you were starting out with the engine running. A higher gear will let the engine turn over easier. Dave

buickanddeere · May 12, 2010

We don't have starting engine problems around here.
We don't leave the switch on and burn out the coils. We change the oil regular and keep the level up. We shut the gasoline valve off to prevent oil dilution. We use clean filtered gasoline in the tank.
Can't blame the engine for some lazy tard abusing it.

Gas vs Deisel

Tom R.S.

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spacechem

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Athol Carr

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MarkB_MI

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Anonymous-0

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Tramway Guy

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Nancy Howell

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Eldon (WA)

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Nancy Howell

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old art

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Tramway Guy

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Mike (WA)

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Anonymous-0

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buickanddeere

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