The YS 45 want's to wind up to make power. Good props to start out with are 11X5, 11X4 10X6 and 9X9 APC. With a correctly tuned pipe or TUNED muffler those props should put the RPM around 16K on the ground and leaves room to unload in the air using 15% and a OS#8 plug. With the right sized pipe the length should be around 11 5/8" from glow plug to pipe's apex (start at 3/4" longer for your setup and shorten by 1/4" increments).
He may have been a tad long on the header and the prop was bit much if he wanted more rpm. The 45 is glow plug sensitive and will like crud if the heat range is too far from an OS #8. Once the engine is running good, try some 30%.... yahoo!
Chris, if you don’t tell him this, maybe he’ll get frustrated and you’ll be right about the engines ownership.
