Re: 94 135 Mercury going from Neutral to Forward Gear
No, Forward gear engagement is spring loaded inside the gearcase, the linkage simply remove the pressure holding the spring into Neutral or farther, into Reverse. If the linkage does move more it is because the cable is not pulling it all the way and when the engagement dogs align and engage the spring forces the linkage to move that last 1/16 inch.
Shift the control into Forward and mark the linkage travel, disconnect the shift cable and shift the linkage by hand, see any difference now?
The shift cable housing has a teflon lining, over time the cable wire wears a 'groove' on both the inside and outside of every bend in the housing as it pushes and pulls. Once these grooves are worn the actual distance the shift linkage moves is reduced. This limited movement causes incomplete shifting which then causes the engagement dogs on the gears to wear rapidly.
Compare shift linkage movement with the control vs manually shifting with the cable disconnected, when you can see a difference it is time to replace the cable.