This time I was careful Gray Beard. I never use castor on my 4C engines. This is a home brew with lab tested methanol and Klotz100 with 20% klotz and 7% nitro. Klotz 100 has 20% castor in the factory mix for a bit more protection for safety, so thats what we use. This engine was a box damaged Tower engine though and was in storage for over a year and half. In that time, I had standard 3-in-1 oil i.e. Singer sewing machine oil i.e. light machine oil in everything including the cam shaft chamber, valve chamber etc. So I doubt that any of that is and issue.

I think I need to move on from the rust issue. My real concern now is the tight compression. Its so tight, the prop is very difficult to turn over compression by hand. It hard enough to physically move the model when trying to turn the engine over. The starter doesnt seem to have problem turning over though. I am concerned that if a valve is binding or something, I may break something in turning it over. Seems to run just fine though

Ameyam