http://www.mecoa.com/gms/manual.htm -Here's the manual for your engine.

"FUEL TO USE

Model airplane fuels are a mixture of methanol, oil, and various additives to improve ignition, add power, and cut down carbon deposits. It is important to use fuel with a castor oil and/or synthetic lubricants, otherwise, your engine life will be drastically reduced. Nitro is another fuel ingredient that is often used. Its function is to "advance the spark". To determine if you need any, or more nitro, start your engine, open the throttle wide open and set your high speed needle for maximum power, then back it out slightly. Do all this with your booster battery connected. Now remove your booster leads - if your motor slows down, more nitro is indicated. Conversely, if your motor speeds up, there is probably too much nitro. We recommend high quality commercial fuel with 10~15% of nitro.

WARNING: Model airplane fuel is both flammable and extremely poisonous. Run your engine only in a well ventilated area. "