D1-30F runs great, but wants to idle high.

I have a near new D1-30F that runs out great. When I start the motor it idles around 800 RPMs for about a minute, then it idles up to 2000 RPMs. I usually let it warm up a little at this 2000 RPM point, then I kill the motor, restart the motor, and before it starts to accelerate I drop it in gear and it will idle at 800 RPMs all day long. I have looked through the oil filler cap with a dental mirror and it looks as the two springs are intact and will stretch when the throttle lever is moved. The idle bolt is backed all the way out, and it wants to idle high even when the throttle lever is disconnected from the throttle cable held back at idle position.

Any ideas?

Thanks,
Randal

This engine does not have an exhaust thermal monitor, just a coolant temperature sensor. It works very well. Thanks though!