M, SM, SMTA carb difference

Hayfarmer · Jun 4, 2014

How much difference is there in carburetors between the M, SM, SMTA? Is it just in jetting of carb?
thanks for any help

D Slater · Jun 4, 2014

SM and SMTA the same for the same fuel type. Metering on a original M carburetor was different. Hard to say what a M has in it now though. IH made 3 or 4 different parts to change the metering plus aftermarket made some for M and SM. Biggest difference in a M and SM is the choke levers are on opposite sides of the bowl.
Originally a M gas and SM gas metering nozzle had different size in part of the three holes and the tip was a different size. Lots of rebuild kits that include the metering nozzle can very on the sizes if you check all.
Main seat size, air bleed size and idle jet sizes could all be different between some carburetors other than the discharge nozzle.

M, SM, SMTA carb difference

Hayfarmer

Well-known Member

D Slater

Well-known Member

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