M carb questions

Charles E. McNelly III · Jan 24, 2009

Hi All,
I was looking at my service manual today and wondered why the carbs were so different between the low compression and hi compression models. Would there be a performance issue using a distillate carb today vs. a gas carb burning the same fuel? My carb is missing the ID tag so I pulled out my parts book and the fuel bowl # showed it to be off of a distillate carb. Seems to run ok, just wonder if I need to find a different carb.
Thanks for the input,
Charles

glennster · Jan 25, 2009

charles, i am pretty sure the distillate-kerosene carbs had slightly larger main and idle circuit jets because the fuel was a little heavier. my 42 m still has the distillate carb, it runs fine on gas, just lean it up a little with the smoke screw. quicky way, tho not always sure fire, is to see if the carb bowl has a drain petcock instead of a plug. the distillates had a petcock so if you konked er out on kero/distilate, you could drain the carb and get gasoline in it to get er started.

Wayne in MN · Jan 25, 2009

Not to worry; just make sure the carb is clean, adjust the idle air acrew, adjust the main fuel screw, and idle rpm's. You do not need a different carburetor.
My oldest son has a 1943 M with distillate carb and runs just fine with gasoline (10% ethanol).
Have fun with the M; it is a great machine.

Charles E. McNelly III · Jan 25, 2009

Thanks for the reply.I had always thought the petcock was a way to tell if it was a distillate carb. My part number shows to be one but the bowl has not been tapped for a petcock hince the thought it was a gas carb. runs ok, just made me wonder.
Charles

M carb questions

Charles E. McNelly III

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glennster

Well-known Member

Wayne in MN

Well-known Member

Charles E. McNelly III

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