I have and OS 160 with a pipe. It ran fine for 10 flights. then it started acting up. At low mid range to idle the engine has a tendency to shut of resulting in dead sticks. There is plenty of smoke from the pipe. I changed the glow plug and checked the tank. What could it possibly be?. Low end to lean?. Today first flight engine was to rich. I leaned it out. Too lean richned it up some. Engine ran fine until I throttle down to enter a torque roll. Engine quit before I got set up. Any solutions?.