Hi:

      I recently had the misfortune to have two engines go very very lean while flying.  I mean that they finally stopped running from being too lean.  These engines were rally cooked when they finaly landed.

      The engines in questioin were a 1950's Fox .25 and a 1970's O.S .35 stunt.  When they cooled down, they both had great compression with no noticable leak down.  They started wih about two flips each.  The engines were black and brown on the outside and the pistons had a black residue on the sides of the pistons.  This residue ended about .125" down fron the top of the piston.

      I was running "Club Fuel" that started with 10% nitro and 25% castor oil.  I added 4 oz. of castor oil to the gallon of fuel just incase I did have a lean run!

     Years ago, a chap with whom I became friends with, insisted that one could not hurt a cast iron and steel engine if one used all castor for a lube.  Perhaps he was correct!

      What about it?  Have you ever ruined a cast iron and steel engine when you were using a high percentage of castor oil?

                                                                                       Stay well,

                                                                                       Frank