Many of the engines I've received in the past were way off. Ralph and Larry made it sound like checking timing was mandatory on all engines.

MTK's engine ran well at first but didn't run well or at all after a while with two different modules. Since the key didn't shear, the pickup would have to move to change the timing. If there was no spark or intermittent spark the magnet could have gone bad. It'll be interesting to see what Hobby Services has to say.