Hello,I have a briggs intek 13.5hp ohv single cylinder engine I just rebuilt.when I go to start it up I have to choke it to get it to start.while its running it back fires through the exhaust and carb.Also the govener hunts.If I choke it half way it will idle high and run without backfire or hunting.I'v tried adjusting the valves from .004 to .006 and cleaned and inspected the carb,adjusted the govener and inspected spark plug gap.I need help.Can someone help me? Unfiled 9/27/09 5:35 am

Hi,
By rebuilt do you mean you had it torn down? Sounds as if the cam is a tooth out of place. Current ignitions have built in advance systems that could compensate (or try) but performance would be poor or erratic.
Peace,
Clarke