8 hp on a homelite snow blower. carb rebuilt. started n ran fine this summer. running this winter has a tendancy to die under load. starts up agian fine at full throttle. i have been able to paly/feather the throttle to keep running and observing some dark puffs of smoke out the muffler. will sit at idle or low speed with no issues. even sitting at hi throttle it runs good. only premium no ethanol run in it since carb rebuild. have not touched it yet but wondering if this is a hi speed adjustment with the carb since lo speed seems no issue? any thoughts?
thanks