The flywheel had the center cut, but will check out the rest. It does seem a little rich at mid range but i've adjusted the low and high about as lean as i dare. May try a different carb. The 15x10 APC did make a slight difference over the MAS 16x8-both are balanced spot on. More testing and work. The little engine spools up fast and has lots of power. I will play with the timing a see if it vibrates at same RPM at 28 and 30 to 31 deg. If i can't get the vibration down it goes in a box! The 26 runs smoother and has about the same power-it could use new rings and that may bring it up. I wonder where these engines are happiest regarding RPM-stock porting??

I will flip the prop a 1/4 turn and see-good idea to start.