I bought a gallon of Sig Championship fuel the other day. It is 15% nitro and 20% oil (half synthetic/ half castor). Is there such a thing as too much castor? I am running a O.S. 46 FX and a 15 year old Enya 60. I have been using Ritch's Brew with 15% nitro and 18% oil. Which would you guys recommend? Thanks for the help.

Ed

I've never got to the point of too much castor but in my ST G51 I'm using 25% all castor. OK, it's far more than it needs but it changes the running characteristics so it's more suited for my purpose. I use 20% all castor in my Enya 60X and Rossi 45 though.

OS Max .35 25 to 28% Castor
everything else 17 to 21% Castor.
I don't think there's such a thing as too much protection, but 17 to 20% is a good compromise between performance and longevity. 15% performance goes up, but replace the sleeve after 3 or 4 gallons. 30 to 35% and performance suffers, idle suffers, but the engine would prob. run forever.

I agree that at some point performance suffers. It's sort of a personality thing too. Some people should use more castor because they need every blessed last rpm they can get. You know, the needle tweakers! When I ran too much castor in my 2 stroke YS pattern engines it just about ruined them. They ran like crap, and carboned up real bad. When an engine developes carbon or lacquer build up it gets ugly too. The composition of lacquer is such that when the engine gets hot, the laquer gets gooey and wreaks havoc with engine performance. When the engine cools all seems fine and on goes the vicious cycle. At that point the engine needs to be torn down and massaged a bit. When I ran too much oil in my Rossi and MVVS engines they did not perform well either. My style of flying dictates total oil in the range of 17%, one fifth of that being castor. Walter Morris told me that years ago to get my profile engines running the way I wanted them to and he was right. I miss him and the old Morris Hobbies.
Whew, did any of that make sense

Thanks. I think I will give it a try.