I was flying my Eagle 2 today and something happened that I'd like to know more about. This is my first year with glow engines.

Conditions:
- Wind N at 10
- 70% Humidity
- Baro - 30.02
- Temp 37 F
- Engine - OS 40 LA with about 15 or so flights on it.
- Fuel - Omega 10% Castor/Synt blend

I was about 8 minutes into the flight, when I noticed the motor rising and falling in pitch (at about half throttle). About a minute later I brought it in on a dead stick landing. I noticed that the fueld residue seemed to be blacker than normal, and it almost looked like there was some carbon residue that had made into the fuel tank compartment.

I eventualy got it running again, after some fiddlin' around. I basicaly closed the needle, and started over tuning it like the manual says for a new engine, and that seemed to get it running again. What happened? What did I do wrong?

Thanks,
Doug