First off, I've got to say I've been flying r/c planes for years, and r/c helicopters for a few months, so I'm not a newbie to glow engines.
I've got to say I've NEVER had as much trouble breaking in and tuning an engine as I have with this one! It will just NOT run for longer than a few seconds, or else it runs at such a high rpm it would be down the road and crashed before I had a chance to pick up the transmitter. Pull starter has allready broken, and no, not from me yanking it to hard or far. Took the starter apart & fixed it, but frankly, I'm ready to either buy a different engine or toss this thing in the dumpster.

ARRRG!