Originally posted by Top Gun 777
Many times burned glow plugs doesn't mean too lean. In most cases t will need adjust combustion chamber volume. By switching fuel it might be different nitro content and it is reason why it stops byrning glow plugs-might be less nitro and it is OK with little too small combustion volume.
About rust-it is totaly strange. Are you sure you use fairely new fuel which was propoerly closed and never absorbs moister?
Edward
Edward, nitro content was the same. Motor was new , I picked up a new gallon from the same shop, can't figure how long it was lying there.