I have a 1974 Merc tower of power with quicksilver throttle linkage and am unable to get it into neutral. I removed the throttle and inspected the internal assembly, which appears to be in good condition-well greased and free of corrosion. It has been a while since I used the boat, and never had a manual for this used setup, so don't recall the precise starting procedure. Does anyone have a simple suggestion of what I might be overlooking?