I just ran my Savage 25 through about 3/4 tank of 20/12 fuel with a new plug and it finally died at the 3/4 mark. I checked the plug and sure enough it wouldn't lite. Both needles were set to about 3.5 turns out and I later opened the high speed to about 3.75 turns out. The glow plug was also not burned up. Any idea what is causing these things to die so quickly?

Ian