30 Evinrude surges at high speed

I've got a 1985 30 Evinrude. I recently lost a piston and gathered enough parts to rebuld the motor. Used block, head, crank and pistons; new rings, gaskets, seals, plugs and wires. I also rebuilt the carb & fuel pump with new kits, and while I was at it I decided to change the seals in the gearcase and replace the impellor. The motor idles great, starts easy, has lots of thrust, but surges and dies at high speed. It will run great until between 3/4 - full throttle. I swaped out the fuel pump for another, and tried new plugs. but the same thing happend. The reed valves appear fine, and there are no apperent fuel or vacuum leaks.

Does anyone have any idea as to what may be the cause of the surging?

Re: 30 Evinrude surges at high speed

do a link n snic on it. if that does not cure it, check you float needle valve, may not be seating all the way, and high rpms pressure from fuel pump, could be forcing fuel thru it, flooding the motor.