Small Engine Problems? Ask an Engine Mechanic for Answers ASAP
The gasket should be available from any good local Tecumseh dealer and it is also avaialble online. I've linked the part numbers to a source. I've also included the part number for the crankshaft seal, since it's a good idea to replace it at the same time.
Side Cover Gasket 37342
Crankshaft Seal 35319
I hope this is helpful.