Re: How to use castor oil??
Since this was bumped: I have been running a 20/80 hobby-store castor/ACE Hardware Ashless 2-stroke on my engine since its birth. I started @ 25:1, and upped to 30:1 after I felt it break in. It's been running great although I eventually ran into trouble due to carbon-buildup and what appeared to be gumming of the rings. This "gumming" caused the rings to loose their springiness enough to negatively effect compression (quite suddenly I may add). I removed the piston to clean it and tried to get what I could of the buildup from out of the ring-channels with a file, but I simply could not get the rings to seat completely; the assembly was too big to get back in the cylinder. Fortunately, I had an extra piston/rings, so I have the old assembly soaking in gasoline. The new assembly returned the engine's performance, so I decided change the mix again...I'm now running the same castor ratio, but at 50:1. I've noticed increased power, and the spark-plug went from a dark-brown to a true cocoa-color, like Chocolate Quick (an American chocolate-milk powder). Oddly, I've also noticed a decrease in operating temperature. I plan on picking up some Dawn Spot Remover (I think that's the stuff that removes carbon well) to completely recover my original piston assembly, but it's good to know that my sudden power-drop was easily and logically resolvable. As for castor in general: I highly recommend it. Although there's the carbon to deal with, it's kept all the moving parts (that haven't been coated in carbon) lovely and mirrored.