Hi Joe,

Like Rico said: Sounds to me as though you're running too lean. A lean engine over-heats and grinds to a halt. Unscrew the needle until you're running as rich as the engine will stand, then turn it back in, gradually, until the heli can lift-off. You need to run rich enough so's to keep the engine cool, but lean enough so's you have sufficient power. With this engine you don't have a whole lot of power to spare, so you have to get this right

Also like Darth said: Use blue Loctite on the cylinder head threads - doing this completely transformed my V-6

I couldn't get away with 15% nitro so went to 30% which worked great. Over time I've reduced the nitro content and found that 20% is the lowest I can go and still keep my LMH flying reliably

Good Luck,

Tony