I feel your pain Dave. Mine was driving me mad and it wasn't the first time it had done it to me. The final piece of my puzzle was the valve clearance (cold and at TDC) needed to be at least .002". Any less than that and the engine was difficult to tune and would start to misfire a couple of minutes into the flight. I believe it had other problems that were sorted during the year and a half it took to solve but the valve clearance was a bogey man lurking under this engine's bed since the day I had bought it. Maybe the cam was ground on a Friday afternoon??

I did consider an electric conversion on the Aries07, but decided against it. I don't have the ancillary equipment to support 10S flying properly, the plane would have wound up even more overweight and (did I mention?) I'm still flying 36Mhz. Despite the horror stories I'm running the CDI and RX from the same 2S Li-Po although they are supplied via separate linear regulators as I haven't gone HV yet. I've got the 2.4 module and a few RX's for the 14MZ if I NEED them for a particular comp.

Any flight cost differences between running IC or electric gets blown away by the travel costs of one comp, so I'd consider it a moot point, but I reckon if I had just bitten the bullet back in 2009 and gone electric instead of IC I "think" I would have been happier. I'll never know??