I thought you were talking about starting? I agree that timing is an issue when running. Timing is not an issue when starting. In our engines timing and the extra compression needed to start are related. So is richening the mixture to start, as a good portion of what will be thrown into the cylinder will not be vaporized and incompressible. I'm looking at it from the theoretical side. We know we need heat to start and in the case of the cold engine all of it comes from compression. This means we need to increase CR. Ignition timing is always at lowest advance while starting an engine, that's why it sounds strange when you say you need to advance timing to facilitate starting. We need to make sure ignition occurs.

I did make a lanova with as large a hole as possible to go through the glow plug hole for the FS26 conversion. Actually the whole chamber was that same diameter. It did not run different than a lanova with a hole less than half that size. I don't see it being a problem for the small engine. I could forsee it becoming an issue with larger engines. Fixturing the head to enlarge the plug hole is not an easy task, if there is even enough material to allow it.

Yes, there probably is a difference between fourstroke and twostroke characteristics.

I picked up some Amsoil ACB today. I took out my FS-40 and ran it up on a god knows how old tank of fuel. I was in a hurry and didn't bother pouring fresh Clutton mix. It didn't like the old fuel but it did start and sorta ran. I mixed up a batch of 20% Castor, 78% ace hardware Kerosene, and 2% Amsoil ACB. Drew some fuel to the carb and flipped the prop and it fired right up. It was warm from running the old fuel. The compression settings were similar to the past. Needle I'm not sure as I changed to a Magnum two needle carb from the .30FS. I was extremely happy with the way it ran and tuned. It seemed to make quite a bit more power, but my tach was not within reach. I was able to lean the top end out so much the exhaust felt dry. The carb might have a problem as I couldn't lean out the idle mix so much that it quit. I ran it about 5 minutes before I had to go. I think this is just the ticket for the fourstrokes. More running tomorrow, maybe some video.

I'll probably pick up my Enya Friday. If I have enough time on the weekend I'll be doing some testing with fuels. I'll post pics of the Enya when I get it.