Have a troy bilt pony 12 yrs.old with 17.5 briggs.Last I used it seemed to lose power.Shut it down and would not start untill about 3 hrs later.When turning over sounded like slight knock.Cranked later and seemed ok.Went to start today and no start.Has new plug that fires,fuel in carb.Carb solenoid ok.Valve clearence ok.Any ideas?Also has 115 lbs compression.I am thinking maybe compression release valve on the cam.
