Rebuild or Replace MH-50 Carburetor

My MH-50 is running badly, and I’m think it is a carburetor problem. Should I rebuild or replace the Carter carburetor #UT-0985?

I don’t see the Carter UT-0985 listed for the TO-35 or any other tractor with the Z134 engine. The Carter carburetors my books show used on the MH or MF-50 are the UT-2418-S and the UT-2612S.

Given the difficulty of getting parts for Carter carburetors, I would purchase a rebuilt Marvel Schebler carburetor. The models used on the MH and MF-50 are the TSX605 and TSX683 which are part numbers 183576M91 and 533969M91. These are available from All States Ag Parts at the following prices.

TSX683 $250 plus $50 core charge
TSX605 $225 plus $100 core charge