MTD snowblowers have been made with many different crankshafts in them. It is very critical that you find out your crankshaft dimensions before starting to look for an engine. Tecumseh made models H30-H40, HS40-HS50, HSSK40-HSSK55, & LH195SA, that are all the same physical size and will replace each other as long as the shaft size is correct. Tecumseh also offers models H50-H70 & HSK50-HSK70 that are all the same size blocks, but these will not interchange with any other size blocks. The same goes for models OHH45-70, OHHSK50-OHHSK70, and OHH195SA which are all the same size blocks, and also will not interchange with any other size blocks. Finally, Tecumseh has models HM80-HM110, HMSK80-HMSK110, & LH318SA-LH358SA that are all the same size blocks, and will replace the OHV engines from 8-11hp. For non-OHV engines, Tecumseh has models OHM80-OHM130, OHMSK80-OHMSK110, & OH318SA-OH358SA that are all the same size blocks, and typically replace the non OHV engines from 8-11hp.
