[crock]

There are a lot of aftermarket fuel additives that work pretty well. I have been using FP60 and FPlus for years. Amsoil and Redline carry fuel additives that are proven to work well. Another commonly used fuel additive is two stroke motor oil. You use the TC-W3 marine rated oil if you are running a catalytic onverter and motorcycle two stroke oil if you are running an open exhaust. In either case you mix one ounce per five gallons. If you Google search an of the ideas I just suggested you will get 50 different threads discussing the pros and cons of each fuel additive. Unlike oil additives, fuel additives have proven benefits. The benefits may not be cost effective, but the additives do the jobs they claim to do. You just have to decide if the benefit is worth the extra price and hassle.