thanks for the reply guys, im running the stock 0.3mm head clearance, actually measured them to make sure because just like you I thought maybe a compression related issue. as I said every plug run looks new, element is always in good shape and silver. if i poke the plug wire while its in the glow starter it starts workin again like the wire is broke from the base of the plug hole. ive tried 10%, 16% and 25% nitro content fuels but issue continues regardless.