I have built the TIM-6 ignition and installed it on a 18cc weedeater engine. The ignition works great. Wish I could say the same for this engine. (really weak!) I calculated the dwell angle using the formula from (av8tor1977)'s post in this thread. I had to mount the magnet as close to the shaft as I could to come close to the dwell angle. I calculated at 7500 RPM's I did notice that with a smaller prop that as I approched 8000 RPMS the engine started missing like it had a rev limiter. (Not enough dwell?) I have ran the engine over an hour on a 1200mha battery, don't really know how long it will run on a single charge? I think I will install the ignition on a ryobi or Mac32 and see how it does. May also try two magnets to increase the dwell angle, but don't think I will really want to exceed 7500 RPM's anyway.