Low Cost fuel Carburator Farmall M

I was going to overhaul the carb on my M. I had picked up the kit before I took the carb off. I had assumed the tractor was a straight gasser as the fuel tank does not have two sections. After cleaning up the carb I found the ID tag and it is a Low cost fuel carb(47387DB).

A couple of questions. With the tractor I got a letter from Rick Tworek at Case_IH indicating the tractor (FBK76832) was built in 1944. In the past he has provided me with a build card for my Case DC3 that showed what options were on it originally. I assume no such build card info is avaialble for Farmalls. Is there anyway to determine if the tractor was originally built for low cost fuel??


There are a few differences in the carb noticeably the fuel adjusting screw and its seat. Also the holes in the metering nozzle are obviously different. According to the service manual there is also a difference in the air bleed to the metering well.

Second question. Can I make this carb work better with gas? Currently it seems to run too rich. Should I get a gas carb or should I get a dual fuel tank and try to run Kerosene (that might be kind of fun....

Finally looking at the parts manual there seem to be 3 different cylinder heads...gas, kerosene and distillate (also valves are different). Is there a casting number on the head that would tell me which I have????

The engine cylinder head (if original) will be marked with the distillate part number (or Kero part number) under the valve cover.
If it was originally for tractor fuel (distillate, or Kero) it will also have a second gasoline tank in front of the main tank, under the main hood, with a hole for the tank neck. and bracket to hold the tank.

THe carb if adjusted to float level, and clean, should work well with gasoline. adjust the load screw inward to limit fuel delivery. If it still will not lean out, someone may have reamed the jet, or installed the wrong main jet. Jim

I don't know what you are seeing on the fuel adjustment screw, but unless someone has already modified it somehow, there is no difference between the distillate/kerosene carbs and the gasoline carb. There may be some difference in the main metering nozzle, but again, it may have already been modified. Some folks do try to improve the performance by drilling out those holes, but usually all that is accomplished is to create an over-rich condition. The exception to that would be IF the tractor has the M&W engine kit in it, and the carburetor has been rebuilt with the M&W high performance kit, then the holes in the metering nozzle ARE bigger. There is no point in rebuilding the carb with a kit for the 47387 carb since you most likely will be running it on gasoline anyhow, so use the kit for the 50983. It will fit your carb. Chances are good that is what is in there now.

There is a part number on the head, but it is under the valve cover. That number will tell you if you have the high compression gasoline head, or the low compression distillate/kerosene head.

The serial number of the tractor will have the suffix "X1" if it was originally a gasoline tractor, "X3" (I think) for kerosene, and no suffix for distillate.

The kerosene/distilate tractors would run just fine on gasoline when they left factory there might be some slight power/fuel comsumption advantage with the gasoline carb but not enough to be concerned about. If you plan on running tractor 2000 hours/year like we once did it might be worth effort to change carb, head, manifold and whatever.

Thanks you all. For now I will just clean and adjust the carb. She isn't used heavily. Manifold is a gas manifold. I haven't pulled the valve cover to check the head casting#...