OMC Shift/Throttle Control

I'm trying to find some information on the operation of a OMC shifter. Can't find a model number on it. It has a tilt/trim switch, high idle lever, key switch with push choke, emergency shut off tether, and a alarm built into it. Also has a single post plug in which runs up to a trim gauge on dash. Just above this plug on backside of box there is a adjustment screw of some type, I've adjusted it both ccw and cw and don't notice any operational difference. Anyone know what this is for, also I can't figure how to set high idle. Thought you started motor, lifted lever then could adjust throttle lever position, mine doesn't respond to this. Thanks, Todd :?:

I don't know if we have the same controls. Mine in on a '74 Merc 500 thunderbolt ignition. It has the push button choke, warm up lever, trim/tilt on handle, key. I don't think mine has an alarm. If it does, I doubt it works, never heard it.
Starting procedure for mine is: warm up lever in 1/2 open position, hold down choke button, crank. Once it fires(and dies), let up on choke, start. It's the same no matter if it's 10* or 100*.

That screw knob should be throttle friction. It adjusts how tight or loose the throttle handle is.

Are you saying that when you lift the fast idle lever, nothing happens?