I actually did that on a Poulan 42cc. It ran perfect. I used 1 gallon of 20% nitro car fuel and 2 gallons of pure methenol. It worked out to just under 7% nitro and 5% oil. It ran very good. Power was the same as on gas. I just ran it a couple times to experiment. I never flew the engine. I have heard that if you mount them inverted they can kill when the throttle is applied if you don't use onboard glow, but I had mine upright and there was no problem with that.