all-fuel switchover temperature

Most all-fuel tractors say to start on gasoline, and then when warm switch to all-fuel. What temperature do you think would be best for the switchover?

Mainly just warm enough for the tractor to run. We would start the old D John Deere and switch it over once it had run just enough to take off. The little amount of gas that the actual gas tank will hold isn't enough to go too far..lol.

operating temperature. other wise your fuel is going into the oil pan. that is why you had to drain down the oil pan petcocks every morning. and that is why the wk 40 tractor tractor engines got worn till they would not run.

Because most are equipped with shutters and hot manifolds, at least intended to have them. The time is reduced when they are used. Temp should be high enough that there is little if any stumbling when the blended fuel in the carb becomes full distillate/kerosene/heating oil-gasoline mix. So depending on what fuel, and conditions hotter than 180 degrees. Jim

I used to have a Contenental engine powering my sawmill. I would run it about ten minutes on gas and then switch it over to kerosene. I would suggest staying with gasoline. Kerosene is more expensive and it's hard on the exhaust system. The manifold on the Continental would be a deep cherry red running on kerosene. It destroyed the old manifold and I had to junk it. A replacement manifold was $800 and that was thirty years ago.

195 to 210F

Reach operating temp, then switch over. Use shutters to help get you there. If weather is cold, use shutters to keep it warm.
Its kind of pointless to try to burn this now. Kerosene is higher than gas to buy. Distillate really can't be bought anymore. Is what it was, was crude oil that wasn't totally refined. Like, not refined all the way into being gas.
So, unless your just switching fuels over for demonstration at a tractor show or something, no need to really mess with bothering with it.
Distillate and kerosene were only burnt back in the day because of being cheaper to buy. Engines actually lost horse power burning that stuff versus straight gas.And those fuels were cheap enough to even make that worth while back in the day.

The old IH temperature gauge that was on my Dad's '44 H that he was able to buy in early 1945 was divided into three sections. The 1st 1/3 was a white section that read COLD. The 2nd 1/3 was a green section that read RUN. It had a small black arrow coming from the top edge of the green section that appeared to point to the N. The last 1/3 was red that read HOT. It was a factory dissiotialate tractor. It had the shield over the dissiotialate style manifold, but it didn't have shutters as I remember. The manifold shield hung on the shed wall for many years with most of the original paint still on it. The lever on the manifold was permanently rusted in the C position as long as I can remember. We always ran it on gasoline. We also had a '44 H that Dad bought from a neighbor who bought a new 1950 M. He paid the neighbor more for it than the IH dealer had offered the neighbor had been on a trade. It was a factory gas tractor. It's manifold is a gas manifold, but the serial # tag isn't stamped X1 like later gas only tractors are. It has a starting tank hole the hood but never had a starting tank installed. It doesn't have the 2 inlet setiment bulb below the main tank. (How many out there know what I'm taking about when a say a 2 inlet setiment bulb?) No shutters or opening/closing mechanism was installed on the dashboard. The carburetors are different, too. I still have both tractors.

I do. The dual fuel tractors had a sediment bowl that had an extra fuel line fitting for the line coming from the auxilery (gas) tank. The valve on the bowl only shut off fuel from the main tank. There was an additional valve below the small gas tank for the gas line. Both valves should not be open at same time, or the fuels would blend.
If the shutters were ever taken off, they generally were never put back on. Especially if distillate or kero were no longer being burned. The mechanisms to open and close them generally became dis-functional (seized up). Even when open, they still somewhat restricted a little air flow.

Excellent description! I was hoping for some one to provide a great explanation, as my original post was getting a little long. Old timers always said be sure to close kero valve first when you shut down & open last when you get enough heat to start up. Do you know why there is an upper & lower petcock on IH oil pans? Bottom petcock was to drain light hydrocarbons off in the morning from the top of the heavier motor oil to prevent dilution of the engine oil on a kero or dis burner. Then fill it up w/fresh engine oil until it runs out of the top petcock. Lighter hydrocarbons would condense & float on heaver engine oil if you let it set overnight.

What year did IHC start (not) putting an extra hole in the hood for the gas burners? I don't have a gas burner H, but my 49 gas burner X1 M does not have the extra hole in the hood for the auxilery tank that was never there.

My dad said that my grand father who owned the 1935 JD B I now have said when you saw a bit of steam coming out of the radiator it was time to switch it over to distillite fuel

Not sure, but probably not before they started stamping the serial tag w/the X1 designation. I've never seen any information on when that designation started, but I know it has to be after the 1944 model H that I have.