Hi all, I was looking for some information or someone to help with a problem I am having with my new Enya 120 4c engine. The problem seems to be with power !! I have a very realiable idle (1950 rpm's) great transition and no sputtering on low end. The prop I started out with was a 14x6 MA and have progressed all the way up to a 15X8 MA. The engine runs normal temperature at full throttle but misses and bangs (almost like a backfire or pre-detonation) at full throttle. With the 14X6 prop I was turning 10,000 rpm's on the ground and with the 15x8 I was turning 9400rpms. I run Byron 15% and the engine is on a Great Planes spacewalker (weight is 10lbs 4oz). It seems to have very little vertical and can not hold any knife edge at all. All parts are seated and sealed (including carb) and valves are adjusted to .05 as per manufacturer specs. This engine was new in box and has had 3/4 gallon of fuel ran through it. Someone suggested dropping to a lower % nitro since it has no head shim for the higher nitro. The plug I run in it is the stock one that came in the box. Will a Enya #3 plug work better? Also there seems to be very little adjustment on the high speed needle as more than 2-3 clicks either way seems too rich or too lean shutting off down the engine.Thanks and any help woudl be appreciated.