Ditto on the fuel line restriction- - - -the vacuum from the pump will make the fuel boil if it can't flow freely. You can check the pump operation with a vacuum/pressure gauge. The pump should pull 10-12 inches of vacuum on the inlet side with the engine running on the fuel in the carburetor, and the vacuum should stay there for several seconds after shutdown. The pressure side of the pump should make 3-4 PSI at idle, and the pressure should stay there for a short time after shutdown, also. A good pump with a clear inlet line will pump a pint of fuel into a catch container in 30 seconds at idle speed.
To give the cooling system a good cleanout, mix about a pint of muriatic acid (used for masonry cleanup, swimming pools, etc.) with about a gallon of water, and add it to the cooling system. Top off with water and run the engine for about 30 minutes. Drain, flush with clear water, and neutralize the acid by adding a full box of baking soda to a fresh fill of water. Run the soda solution for 10 minutes, drain, and rinse. When you're sure it's clean, run a 50/50 mix of antifreeze and water.
Jerry
