My UMS 9-99 seems to have very little compression when I turn the prop over. It is very smooth but offers little resistance to turning over. When I put it away last fall I went thru my usual routine of injecting after run oil and air tool oil as I did after each flying session. As I recall it had more compression than it seems to have now. As I get ready for the next flying season I would like to address any problems early on.
John