I have a Tecumseh 4hp engine that runs great at start up,after pushing primer bulb a few times...however if it runs for say 5 minutes it then quits...like it runs out of fuel....and it will not restart regardless of how many times I press the primer bulb..If left for a period of time..like 4 hours... press the bulb and it will run .. but wont run long..I have removed the float bowl..and cleaned the bolt and the bowl checked the float to be sure it moves freely..and all is ok ....I am at a loss as to why this pice of &^%%&^ will NOt run..Oh yeah have already cleaned the flywheel up..and the coil..and replaced the spark plug with a new one....