Hi Bax;
I have another question for you. I took your advice and changed props on my engine I am now running an 18x10 Master airscrew scimitar wooden prop. and just to be on the safe side I changed my tank to a 3 line set up with a large size clunk on large diam. fuel tubing all the way thru for the fuel supply line. The problem is now I only max out rpm at 5200 and there is no noticeable change when I try to adjust the high end needle and my transition is still rough. at all throttle positions the engine doesn't miss a beat it just doesn't want to transition from low rpm to high any ideas on what I should do now?

Lee,

It's hard to say what the problem may be. With an APC 18 x 10, we can turn the O.S. Max 1.60 FX w/stock muffler at 7,900 RPM. You're turning 2,700 RPM lower. The engine still may not be getting enough fuel.

Try opening the idle needle a LOT and resetting the high-speed needle. You'll likely have to start the engine at part throttle because the idle mixture will be too rich to allow any kind of decent idle. Get the top-end set first and then try the bottom end.

If all else fails, and you can't get any better performance on a test stand, then there may be more wrong than we can diagnose through some emails, and the engine may need to get into the shop.

how is the compression the motor may haqve had a lean run and now is scorched...

Hi Bax. Well problem is solved, the 18x10 is turning 7800 rpm I don't know how much thrust the engine is developing yet, but by the way my plane is moving I can tell it's better than before. I found that some trash had gotten into the carb and was creating a small restriction that would starve the engine of fuel. Cleaned it out and now all I can say is wow what an engine. And it transitions perfectly at the factory settings. Thanks for all your help.

Glad to hear that you're problem's solved! Trash'll do it every time!