One thing that I'm not "getting" is you've talked about shaft splines and swapping shafts...  and also that you haven't removed the "mousetrap" spring and both engine have the spring installed the same... I'm not sure if you can change the shaft without disturbing the mousetrap spring? (I suppose if you're careful it might not pop off tab when pulling shaft, I'm usually not that lucky or maybe just too ham-handed.) Maybe both engines have spring wrong?

Here's a pic of what I'm seeing in my head and trying to describe.  "Claw" in circled in red.    "Mousetrap" spring is #3.... "Shaft" with splines that I'm thinking of has arrow pointing to it. 

If the mousetrap spring is installed correctly the claw will always be pushed back to the same centered position when you stop pushing down or pulling up on the shift lever (partially shown to the right of e-clip #8)   Turning the eccentric screw...  which locates the center of the mousetrap spring...  moves the claw to center it on drum pins.

(Note that parts diagram shows eccentric pin 180 degrees from where it goes if my memory is correct... pin is in the cutout and tab sticking up on shaft is in in between the arms of the spring, I added second picture to show what I mean)

If the spring is not installed correctly, claw will not be solidly pushed back to center by the spring and the eccentric screw won't work right.




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Oh, and I added arrows in second picture showing washer and clip under shift lever... make sure those are installed before installing clutch cover.

There's a minor possibility but not likely--that--if where the spring fits over the arm tang, the tank is bent from square on then it'll upset adjusting. Also i have seen spring ears bent by someone manually tweaking the ears & ended up at an angle rather than straight up from the spring winding. Doesn't take much of anything like that to offset the eccentricity of the screw. But i don't believe it's likely without someone having done 'bad things'. For the lever splines to be twisted it's had a good hit on a rock or accident. At worst it might brake off the eccentric screw but probably break the case too where it screws in. Na, i don't believe any of what i just said has happened. Look forward to pics.

Thank you guys for going with me on this. Looking at Dave’s video his tangs line right up. I realized mine will get into alignment with finger pressure on it pushing to the rear. Maybe I am overthinking this as when the the shifting is going on it pushes the pins fine and seems to go through the gears. I do realize that the eccentric screw wobbles and I have not snugged the jam nut and checked. The pressure kicks back on the screw and moves it in its hole.Got another 12 hr shift tomorrow and I’ll do that this week. The play in the screw may be why it is rolling the tangs rearward. As stated I’ll get the micrometer and snug up this week. I feel the springs are right Mark as the screw is swaddled by the two ends of the mousetrap. Waiting on my seals…

Ok, by wobbly i was just meaning screw turn eccentricaly--being a smart arse lol. But you bought up a point of the screw wobbling loose in the thread while ya playing & before nut it nipped up. So maybe not a total wasted wobbly comment haha.