Thanks again for all the info, guys. I talked to
Carlson, and he suggested I use a dremel
tool with a cutoff wheel and make a small
cut across the top of the cylinder to allow
any pressure build up to escape. I did that
and now the compression screw stays where
I put it. Apparently there was enough pressure
between contra piston and head to reduce the
pressure against the screw and allow it to back off.
The engine still starts and runs fine.
Ken