Here's the story... 1995 70HP Johnson that sat for almost 5 years. Emptied the gas tank, added new fuel lines, rebuilt the carbs, new water pump, new plugs, changed the inline fuel filter. Compression checks out at 128-126-127.
After some intial problem which have been solved, the motor idles and runs great throughout the exceleration range. However soon after getting over 5000 RPMs it will run great for a few seconds and then begin to surge and stumble. The higher I go in the RPM range the worse it gets. Eventually if I throttle up and back off it will settle in and run almost perfectly up to about 5000-5200 RPM's. After that if I throttle up again after a few seconds it will start to surge and stumple again. It seems like it wants to go but just wont break thru. It will jump up to 6000 RPMs for a few seconds and then drop back to 4500-5000 and back and forth.
The ball stays hard. I'm on my second new tank of gas. I tried it on a portable tank to eliminate tank vent or pick up tube problems and it did the same thing. I'm contemplating the fuel/VRO pump but don't want to go down that road until I'm sure because they're not cheap. Besides it almost seems to inconsistent a problem to be that. One note, it almost seems to be worse when I'm cornering or bouncing but I'm not really positive about that.