I have an old Toro push mower with a B&S 3.5 hp vertical shaft engine. It has new spark plug, and carb cleaned and rebuilt. This machine is now 35 years old but starts on the first pull of the cord. Only problem is after 15 minutes of perfect running while cutting, it starts sputtering and then finally quits. Then when I get it started, again, it sputters a few times and quits again. Won't run right until it cools down completely and then the fun starts all over again. Fuel tank has been cleaned, fresh fuel, gas cap is fine (vented). I don't know what else to check. Any ideas, throw them my way, please. :help:
Duane
Duane