I'm having problems with the engine being sluggish until it comes on the pipe which it starts about 75% throttle. It is very hard to have any throttle management. Someone said they thought the pipe was short. I have not measured it from the glow plug yet and I'm not really sure what measurement it should be at. My engine has the greves pipe running F type plug. The engine seems to idel real well but it is real weak in the mid throttle area, but when it come on the pipe it has no problem going vertical with a 2 meter eclipse. Any suggestion would greatly appreciated.