Puzzled about Shifting

[BB63QM]

Bought a boat with a 90% spun prop…chased issue around mercontrol, shift cables and lower unit with several failed trips to the lake, only to finally hit 100% spun

Easy FIS: new prop

Now: prior to raising lower unit, I have a good FWD,Neutral, Reverse and Reverse-lock cam alignment.

Once raised, whether I raise in Reverse, Neutral or Forward, once I shift to Neutral or Forward, I can’t get back to Reverse.

Forward to Neutral (just back of straight up, where the start/click happen/s, on the back line of the ‘Neutral Zone; doesn’t start if straight up) goes from free spin to locked CcW for Forward

Forward to Neutral: Straight up…still forward; to the click: free but ratcheting.

Neutral to Reverse: carefully back to the corner of the MerControl, Free Spin Neutral. Carefully moving further back, either static and expecting to bump, or with my daughter turning the prop but hand….prop stays free.

drop Unit: LU is I. Neutral and readily shifts to reverse.

I thought there was not enough reverse room for the upper shifter, so I reset neutral forward so now forward is 11.00, neutral is 10:00 and reverse is 8:00.

See video of upper shifter, MerControl, and ShiftCable slide: follows pattern above:
N to F (10 to 11)
F to N (but still Fwd) (11 to 10)
F to N (10 to 9)-catching neutral)
N to Rev (9 to 8, no resistance)—Freeport
Further Reverse—free prop

What’s next—-guessing adjust the shift cable to push further back on slide but not as far as before, but want to hear from others in case that doesn’t work.(my last change was moving the adjuster back about 6 turns, so I’ll try 3 in the other direction, see if that finds the sweet spot where the upper shifter had rotation space and is pushed far enough back to engage Reverse (as is, I think I’m just
getting back to it)

 

[BB63QM]

Bought a boat with a 90% spun prop…chased issue around mercontrol, shift cables and lower unit with several failed trips to the lake, only to finally hit 100% spun

Easy FIS: new prop

Now: prior to raising lower unit, I have a good FWD,Neutral, Reverse and Reverse-lock cam alignment.

Once raised, whether I raise in Reverse, Neutral or Forward, once I shift to Neutral or Forward, I can’t get back to Reverse.

Forward to Neutral (just back of straight up, where the start/click happen/s, on the back line of the ‘Neutral Zone; doesn’t start if straight up) goes from free spin to locked CcW for Forward

Forward to Neutral: Straight up…still forward; to the click: free but ratcheting.

Neutral to Reverse: carefully back to the corner of the MerControl, Free Spin Neutral. Carefully moving further back, either static and expecting to bump, or with my daughter turning the prop but hand….prop stays free.

drop Unit: LU is I. Neutral and readily shifts to reverse.

I thought there was not enough reverse room for the upper shifter, so I reset neutral forward so now forward is 11.00, neutral is 10:00 and reverse is 8:00.

See video of upper shifter, MerControl, and ShiftCable slide: follows pattern above:
N to F (10 to 11)
F to N (but still Fwd) (11 to 10)
F to N (10 to 9)-catching neutral)
N to Rev (9 to 8, no resistance)—Freeport
Further Reverse—free prop

What’s next—-guessing adjust the shift cable to push further back on slide but not as far as before, but want to hear from others in case that doesn’t work.(my last change was moving the adjuster back about 6 turns, so I’ll try 3 in the other direction, see if that finds the sweet spot where the upper shifter had rotation space and is pushed far enough back to engage Reverse (as is, I think I’m just
getting back to it)

 

[BB63QM]

More video that didn’t fit (I guess)

 

[BB63QM]

And the last

 

[BB63QM]

Dismantled MerControl; all appears fine there, except that the little pressure rod flew through the air like wheel nuts in Christmas Story…lost in a Tony bush…looking for a spare in my supplies)

 

[BB63QM]

Ok. While I’m waiting for the postman to bring me a new detent roller for the MerControl (damned if I didn’t find (hand and knees metal detector in thorny bush)…then it flew away again…direction unknown), I did some more tests

Good news: shifts well at the LU
Good news: MerControl seems right
Bad news: seems to be skipping i. The upper shift linkage.

So, with the LU down, I used a borescope to look up into the shift shaft coupler. The splines are completely chewed away for the first half of the coupler (as compared to my spare Shift shaft that I use for manual LU gear shifting, which has splines all the way.

So….what to do.

I can see that the lower coupler on the upper shift shaft (93960A1) is a “removable” part. I use quite because I don’t know how removable it truly is.
Based on looking at my spare, to top-shaft arm is held on my a roll pin (bent metal shoved in a hole to hold the link).
—-if pulling the shaft out as a whole, how do I remove this pin (if trying tapping out the pin in my spare, but it didn’t budge.

Maybe I just replace the coupler at the bottom. I can’t really see with the shaft housing on, but the new coupler shows a hole in the side where I’m guessing another roll pin is, BUT my spare seems to have it’s coupler braised in place…no hole, no pin…both ends of the shot show burn marks.

I’m guessing that the next step is to drop LU, drop the shaft housing, and see whether or not my shaft coupler is removable.

Any hints to bear in mind as I continue down this path???