OK here it is...when i first start up and get it warmed up, it runs great...about 1/2 tank and it cuts out at full throttle...i richened the high speed needle valve to 3 1/2 turns, plenty of smoke, idles fine, but still cuts out at high speed...cracked tank?...broken fuel line? no evidence of this...whats my prob...it runs perfect til half tank!...hmmm...confusing...i've been runnin nitro for 12 years...oh, and i changed the plug, and filter is brand new, and all needle settings are at break-in level. thx for the help!