Update on stuck ring - Vince et al suggested just applying a starter until it started. Downunder cautioned to put some castor in the cylinder, (I added 3 drops in the glowplug hole) but it worked! It took about 10 seconds on the starter before it fired. After about two minutes running, I shut it down due to a loosening muffler. The compression was better. Fired it up again and ran for another few minutes. The third start was a hand start after 4 flips.

I'm using some old Cool Power fuel, (18 months), with an extra 6 oz. of castor for running older engines. Rpm was 11,000 with a Rev-Up 11 X 7 1/4. It's a little low but I think fresh fuel will help.

I probably should still replace the ring, but I'm happy just to get it going this well.

Martin