A stuck lift or aux switch would command it on fast idle.

you don't mention a serial number, and the correct answer may well have to do with the serial number series, as one of the things that changes is the accelerator linkage.
I guess the question is "how high is too high"?
You really should be able to idle it down to about 700 rpm unloaded. and actually you should be able to idle it down to where it doesn't run, somewhere around or below 500 rpm)

Still having this problem, any help out there