Check to make sure the cold HI idle solenoid plunger is not stuck extended. There is a idle screw on the throttle side of the IP to adjust the idle with a warm engine. See below.
When you turn the key on, then one cycle of the go peddle extends the cold HI idle solenoid plunger, it de-energizes when the engine head reaches 120 degrees.Then the idle goes back to the normal 650 RPM.