Hi,
Something doesn't make sense. For it to rev that high, the throttle plate needs to be open and if the cables are removed, that shouldn't be the case. This does have a carburetor, correct? If so, the next thing I suggest is to confirm the throttle stop screw is adjusted.
If you look at the pic below, I highlighted the screw. If you tighten it, the RPMs will increase. If you loosen it, the idle speed will stop. Make sure that it isn't over-adjusted. At idle with a manual transmission, this should idle around 800 RPMs.
Let me know.
Joe
See pic below.
Image (Click to make bigger)
Wednesday, December 21st, 2022 AT 6:55 PM