A friend of mine suspects water is in his fuel tank.Is STP water remover(yellow bottle) safe for an oil-injected suzuki 140hp 2 stroke?I know about seafoam and we mixed it up in a 3gal tank and ran it through the carbs to decarb.But it is $6 a can and his tank is about 35 gals.If STP is not 2stroke compatible what auto parts chemical will work?"Marine" additives are very expensive. Thanks