Universal M18 idle high

[MLW9110]

I've got a mid 80's Catalina 27 with a Universal M18 diesel engine. I'm having problems adjusting the idle. The throttle lever arm on the top of the engine doesn't return fully to the idle stop. Engine idles at a higher rpm than I like.
Is there a spring that is supposed to return the lever to the idle stop? I see that the governer uses.2 springs. There is also an idling spring at the.back of the engine but I haven't been able to find any information about replacing or adjusting it.
Teleflex cable adjustments don't help return the arm to idle firmly.
Anyone have experience with this?
Thanks,
Mike
Bremerton, WA

[Paradox111]

Could be the control rack pin on the fuel injection pump has dislocated / or come out of the Vee Notch. The Vee Notch moves fore and aft via thottle control. On my M20 I had to remove the air intake, to remove and reinstall the fuel injection pump with the control rack pin into the center of the Vee Notch at idle.