I have had to go to a methanol base fuel on the four stroke engines. The four stroke engines burn such a small amount of fuel and the carburetors were metered for methanol fuel. When you cut the amount of fuel used to as much as three times, the carb adjustments get very critical, especially in hot weather. Plus you can't get a good mid range adjustment. I have done a lot of fuel testing this summer and the four strokers run very well on just methanol and oil fuel, FAI fuel. When you can control timing you can control detonation, plus add power and turn a larger prop. Nitro doesn't seem to help top end power much but the engines do run a little nicer with a little nitro, 5%. What I have been running is a mixture of 50% gas, 40% meth and 10% Super Klots that has 20% castor oil. Many of the fliers want to use a methanol fuel altogether, so they buy a 10% nitro and about 10% oil fuel. I still think that most of the four stroke fuels on the market have too much oil.

They are trying to control overheat by adding oil. The overheat is not caused by lack of lub but by detonation which is made worse by trying to run too lean of mixture. When you can control timing you can stop detonation and your four stroke engine will run cool even with10% oil. I have run my Q.S. 1.20 many hours with a 20 to one mix with no problems. I am not recommending this at this time until I have time to do some more testing. I run the new engines on 12% oil and then go to 10% when they get some time on them.

B.K. Products in Denver sells a very good four stroke fuel. He also sells a Tartan fuel that I like for the four stroke engines. I believe Bill told me it is 7% nitro and 10% oil. This is the fuel that they are using in the Saito 2.7 Twin in the Denver area. If you want to use a gasoline fuel, you can restrict the carb barrel to help on the carb problems and the touchy needle adjustment. I restrict the Q.S. 1.20 to 1/4 inch. I even do this on the methanol fuels. You can add about 25% low nitro glo fuel to your gas and oil mix; this will help a lot. I have had reports of guys trying to run their ign. four stroke engines on the same fuel they use in the Quadras. This is not nearly enough oil and will cause problems in a hurry. DO NOT DO THIS!! Well, by now you are probably as confused about fuels as I am, but we are getting there.