Small Engines (Lawn Mowers, etc.): Lawn vacuum wont start, diaphragm tank, briggs stratton

Question
I have a Briggs & Stratton 4hp model# is 112212-0654. I could not get it started and found old gas in it. The gas was yellowish.  I added acetone to the gas in hopes of removing any gum. The engine did finally start and ran for awhile. Two days later I tried to start it again and it wouldn't run. I tried starting it with starting fluid and it seems like no gas is being taken into the carburator. I checked the pump gasket for tears and there wasn't any. I am not sure what to try next. Any suggestions?  

Answer
For dirty/old fuel you really need to remove, dis-assemble and clean the carb with compressed air and carburetor cleaner.  Drain the fuel tank and clean with compressed air.

You will probably have to replace the diaphragm, tank to carb gaskets and maybe the intake gasket.

How old is the engine?
Let me know.
Eric