I am writing to tell about a motor that was running poorly, it was misfiring, hunting, and running low on power. I also had the carb overflow twice. I had recently freshened the motor with new rings. I removed and cleaned the carb, still running poorly. I was thinking the needle and seat were leaking, so I replaced it@ ($25.00) still running rough. I was still convinced it was a fuel problem. Thinking maybe a fuel pump,($25.00) as the filter never completely fills with gas. I then got on this site and read about valve lash and decided to check the valve clearance. They were too tight. I set them at .005" and now it is running smooth again and the fuel filter is full even at idle. This I believe to be a result of poor crankcase pressure due to the valves not closing properly. Awful glad I did some reading before I bought that fuel pump.