Hey Everyone. Have got a DZ that has been running exceptionally well. Suddenly last week, had a dead stick, then the next day had to adjust pump to get it to start, and finally ended up turning the pump in 1 full turn to get it to run. The RPM was noticeably lower and so were the flight characteristics. It seemed as though it just wouldn't lean out at full throttle. Idle and running were still continuous, just not the same performance. Transition, once pump adjusted each time was good, but did have to adjust pump each time. I do clamp the fuel line between flights soon as landing, and keeping clamped through the first start up cranks.Through our contest this weekend I had to adjust the pump every flight to get it run and run-up.

I did change all the fuel tubing, checked the valves(which were in good shape) and changed the plug. All these did not affect the performance.

Magnum DZ fuel, NMP Header, Hatori Pipe, APC 16.5X12W.

My first thought is maybe the diaphragm needs to be changed but it is different than the other YS ones.

It is strange that this happened "all of a sudden"

Any other thoughts?? Thanx in advance

ed