While hovering my Raptor the engine leaned out and died. No restarts. I have dismantled the carb.twice. No debri found. New fuel lines and clunk line. took out tank and pressure tested under water. all OK. If I go full throttle and turn over with starter it will draw some fuel. close to idle and hook up igniter, it will start right up for 2-3 seconds and burn of fuel and die. The fuel lines readfily flow fuel. No obstructions. I do notice the high speed side tube inside the carb. extends inside the low speed adj. side tube looking down the carb. from the top. In fact this same high speed copper tube extends all the way to the opposite side of the carb. barrel opening. I thought they were supposed to meet in the center. Got me baffled. Ron

It sounds like you low end mixture is closed too much. Look at the manual and reset it to factory settings. I've set mine like this and it seems to work ok for starters. With the throttle closed completely turn the low end mixture screw (inside the throttle barrel) all the way in and then back it out 2 1/2 turns. That should get you close. Also set the high end needle about 1 1/2 turns out.

Also be sure you have a good glow plug. I'd try a new one just to be sure. Sometimes they will glow ok with the ignitor on but won't allow the engine to run.

Thanks Scott

Got it going again with low end adjustments.
Baffles me why it changed so much while in flight.-running good, lots of smoke and then lean. Low end not adjusted since new and well into 3rd gallon. OH well! Ron Carl

Is there a chance the low end screw was loose enough to vibrate out of position? I've seen this on SH engines and the fix was to wrap a few turns of Teflon tape on the threads to hold it. Be sure to use a very narrow strip no wider than the threads.

I don't remember if there is an O-ring on the OS engine low mixture screw or not. If there is it could be dry or cracked.

Glad you got it running anyway.