1988 Mercury 150HP XR4 starving for fuel at top end

[Joe Castellucci]

I have a 1988 XR4 150HP that runs fine at low to medium RPM range 3/4 to WOT it starts to fade and loose RPM's when I pump the primer blub it picks back up and runs great no missing or sputtering at all. I have replaced everything from the tank to the engine except for the fitting on the engine where the fuel line attaches. Rebuilt the fuel pump still same symptoms. I'm about to make an anchor out of this thing Help!!!!

 

[BIGFLAT]

Is this fitting on the engine a detachable type, twist to take of/on??? I had the same problem. There was a piece of trash against the ball in the fitting. I hooked it up without the fitting and have not had a problem since...BF