1988 Evinrude 90HP Random Revving Up

I have an '88 evinrude 90 hp that hasn't been running right. It's new to me and I have deleted the vro pump and installed an original evinrude 88 style fuel pump, new ignition switch, rebuilt and cleaned carbs, new fuel lines, new plugs (champion QL77JC4 gapped at .040), and gone through the electrical with new waterproof marine grade connections. My problem is this, when I have the motor in neutral and idle, the rpms randomly jump up 500-1000 rpm. Im baffled as to what could be causing this? The plug wires are new, newer power pack, and new ignition coils are on the way. Does anyone know what could be doing this? I was sure that it was a fuel issue when I went down the carb rebuild road. Any help or suggestions would be greatly appreciated. Thanks in advance.

Welcome to the forum. Did you make sure the linkage to the trigger coil, under the flywheel, is secure and operating smoothly?

Thank you for the response. I will definitely check that. Could that cause the sporadic increase in rpms?

Right....it would change the timing.