The improper use of the ethylene glycol, (anti freeze) will cause the aluminium to turn dark. Plus it is very expensive.

Another method that has proved successfull is the use of the Dawn Power Scrubber. (This stuff is designed to soak pots with cooked on grease over night to be easily cleaned) You can find it at Walmart, Kroger's and other supermarkets.


Disassemble the engine and put the parts (including carburator) in the a pot of hot water with a hefty amount of Dawn. Let sit for several hours. The water does not need to remain hot. I will let my engine sit in the solution over night. Then take a brass parts brush and clean the stains and cooked on castor oil off. It takes a little, very little, elbow grease but the engine comes clean like new.

I lubricate the engine while I re assemble it with Marvel Mystery Oil. I then put the oil engine in a quart sized zip baggy and store it until I need it.

Frank