Local NAPA recommended Sea Foam, he mentioned sta-bil is junk since they changed and diluted their formula. I'm still on my 1st can of Sea Foam. If you have a gummed up carb and can get the engine running at all, he said put about 1 oz per quart (for small engines) of sea foam in the tank and run the engine. I did this trick on a balky Scahs chain saw and it helped.