Trying to Tune my ThermoQuad

First find the leak. Also, a whistle can come from the primary side as well.

If the carb doesn't idle down and adjust RPM wise with the screws, your running to rich.

Idle screw counterclockwise out to lower the idle untill it almost wants to stall, adjust the 2 screws upfront for higest RPM, turn idle up to what it is to be, 750 rpm or what ever.... re-turn the 2 idle screws and leave it be.

The intermintent rise and fall could be the ignition. Stock style systems have a high misfire rate vs other systems.