tecumsuh 8hp snowblower,it has been sitting for 2 years according to last owner, it will start but during this time engine is running, oil coming out of valve cover hose, shut it down once i noticed this ,it will only run for a short time with a lot of backfiring , tried to adjust carb , no effect , please advise.
check the oil before starting. when it is fully settled in the crank. then run it until you see the oil come out the valve cover hose. then shut it off and quickly check the oil. If it is low it may be that an oil return hole is clogged. I a just guessing, it happened on one of my cars.
after sitting two years it might be time for a tune up. Some new gaskets, filters, plug. and carb cleaning. Or you could just change start with a new plug, filters and such, spray carb cleaner while running before changing all that stuff.