I bought a Sea-Doo boat that runs a 2cyl Rotax engine. Well the thing is easy enough to work on. But if I had known what I knew now about the boats...I could have / would have turned down a few boats before buying it....because I failed to do a few simple compression tests, cavitation tests, check out a few other things.
And I assume the same applies for snow machines.....in fact I think Rotax makes snow machine engines?
Anyways don't buy yourself a problem, get out on a forum with sled owners and ask for advice.
There is usually even a FAQ: Buying a (insert product here).