"There is a set screw on the linkage that goes against a stop to
adjust"

That is what I can not find. I have looked all over and can not find
it. I'm not a boat mechanic by any means but I have worked on auto
engines. There is an arm that goes to the fly wheel that when I move
it back slows it down, but I was thinking that adjusted the timing and
I did not want to set the idle by changing the timing. I did read
somewhere that on that model, that was the only way. Any help would be
great.