I just wanted to post this in case others are having the same problems
I had with mine this has worked on two engines so far
We were having peoblems keeping the engine running at low speed
and landings were dead stick more then running
the fix was a hotter plug I use the Enya #3 with cool power 15% and it was like night and day
right from the first start up with the new plug I could hear the engine wake up
and now it's a real runner this motors make good power.
Good luck
Ed