I could use that boat motor
srdave, I'm not 100% sure,but it looks like an old moped,or perhaps a snowmobile.If it didn't have the belt drive it may have been one of those Funky first personal watercraft.I'm betting snowmobile myself.
If you should decide to get rid of it please let me know.I has a small picklefork(boat) I built.It could use a powerplant,and its only about 4'X8'.
