After being put up for the winter, I've put an older .63FZ on a plane. This engine has less compression than my .63FZ-S. Just looking at the FZ, it looks to not have been run much. I got this engine used. If it's not broken in, will the compression build the more fuel that is run through it? Last fall when I ran it, it ran fine and had the same amount of compression.

Fuel: Cooper's 30%
Plug: OS F plug
Prop: MAS 13x6 Scimitar