the Gen II topmount (see below service bulletin from when the Gen II came out) has the friction control set at factory (i.e no adjustment).
The one on our Ocean became pretty loose (lever) so we stripped it down and tightened it up as well as making up some new bushing.....be warned though its a PITA as the push button fast ilde /gear disengage is likely to break when /if you try to remove it to tighten the main shaft... Its designed to be pushed in once the unit is assembled and has barbs preventing it being popped out without breaking....we ended up modifying it so it is in two parts with an allen key fixing between button and shaft (so it can be worked on in future).
The neutral position is held (agree with you re no lock) with a roller bearing and a pile of sprung steel sheets in the top of the unit....all a bit fiddly IMO.....not a great piece of engineering
Also, there is threadlock on some of the fixings so they are likely to sheer and need drilling and tapping /replacing etc.....In short its not really designed to be taken apart to its original components.
You can ease /tighten lever friction a little by tightening and slackening the small nylock nut half way down the casing but its not the correct way....if yours is loose, try giving it a turn, it may improve things.
TBH its not a very good control unit IMO, but if you have the time /inclination it can be worked on despite not being designed to be.