Small Engines (Lawn Mowers, etc.): tecumseh 5 hp hssk 50, blown head gasket, thump thump

Question
My snowblower never failed me until yesterday.While idling it quit ,gave a small puff of smoke and would not start.The spark plug is wet and fuel is definitly making to the carb.Pull cord is seems to spin the engine freely(like theres little to no resistence inside) with the choke open and a little tighter with the  choke closed. Is my flywheel key gone ? I stored the snowblower correctly and freshened it up in the begining of winter.I also have a gasket set on order for it .Your help will be greatly appreciated,thanks in advance.

Answer
It sounds a little more like you have lost compression.  When you turn the engine over slowly, you should feel and hear a good 'thump, thump', regardless of the flywheel key's condition.  I recommend you check for a blown head gasket and inspect the piston, cylinder and valves while you have the cylinder head off.  Hope this helps.