Dave
The following is my observations of a problem that someone else and myself were having concerning deadstick problems with YS. Engine was adjusted on the ground and top end was richened down 3 or 4 hundred rpms and low end would idle at 2100 forever. Prop was
APC 15 x 4W, fuel Wildcat 30%(Jack Youngblood 23% oil)

"I had the same problem with my 91AC. It ran great on the ground and quit in the air. One thing you didn't mention was whether the engine was hot or not. When my engine quit, both times it was too warm to keep your hand on even though it was uncowled. I was flying at 1/2 throttle or less both flights. I richened the reg. and am now waiting on a decent day to try it out. If the low speed needle controls 1800-2400 rpms, and high speed control top end, then is it possible that the mid-range is controlled by the regulator, and running too lean will cause the over-heating and dead-sticks? Just askin?"

This is from the YS Club forum. Any ideas would be appreciated.
Doug