My snowblower will start. Afer 30 seconds it stops. I have to wait 30 minutes and it does the same thing allover again. Could it be just a little amount of gas from last year left over?

I would definitely discard any and all fuel from last year, start with fresh. Drain the fuel line too and replace the inline fuel filter. I think your carb bowl fills and allows the engine to run but the bowl doesn't refill fast enough to keep the engine running. A new fill and fresh gas may help. If not, remove the bowl and flush it with carb cleaner. Also remove and clean the needle valve and seat with carb cleaner. If yo use spray carb cleaner be careful and wear safety goggles.

Check your gas cap and make sure that it is vented (Black rubbber washer that fits the gas cap) if not buy a new one costs about 5.00 bucks. Had the same problem and I brought it the repair shop. The sales man knew the problem right away just by looking at my cap and noticed that there was no washer.Problem fixed and now runs great. The reason it keeps on stalling is because vapor lock.