Hi Fellows: In the box my ASP .75 came in there was a white slip of paper which stated," FOR LONG ENGINE LIFE, ADD 3 OUNCES OF CASTOR OIL TO EACH GALLON OF FUEL". Well, at that time I was using Sig 5% nitro all castor oil fuel. Let me tell you about cleaning a model after each flight. When the weather here in Oregon turned cold, my engines really did not like to run very well. Purchased some 15% Sig all castor fuel, and added one third of a gallon to my remaining gallons of 5% fuel(yes, I removed 1/3 from each gallon first) This increased the nitro content some, and my engines ran very well through all of the gallons in stock. I now add only one ounce of castor to a gallon of 10% Sig all castor oil. This has reduced the model coverage of oil, and made all of my engines run well. I believe the use of this oil content will extend the life of my engines. Engines of the sleeve bearing design will really benefit from using an all castor oil fuel. Four stroke engines are a new kind of animal which needs less castor oil.

aerorich73