Shift shaft issues

This must be a popular thread topic but my case might be unique, I'll try and be brief.

1. Bought boat, 1980 Sea swirl 470 Mercruiser SN 5369977 (Alpha 1 Gen 1 Lower Drive). Took it out and it runs like a champ and had no issues shifting F-R.

2. Previous owner said impeller needs changed in lower, hadn't been changed in 3 years or so.

3. I AM a mechanic (but this is my 1st boat).

4. Looked up procedures and even watched video before attempting water pump kit install. Easy job.

5. Put boat in FWD

6. Split lower from upper.

7. Replaced pump.

8. Ensured lower was in drive (FWD gear) or so I thought.

9. Installed lower (not shifting), dropped unit, checked fwd gear again, installed, (still no shifting), tried this four times. Adjusted shift cables, no joy. Verified upper (intermediate shift shaft?) was aligning properly with lower shift shaft and that mechanism was moving with shift lever when throttle moved from F to R. Good.

10. After dropping again and closer inspection of shift shaft, I determined something was wrong inside the lower. The shift shaft did not have a positive clicking or "feel" like it was shifting the shift crank and working the spool. Even when I spun the prop shaft and drive shaft. It did not seem like the shift shaft was positively engaged -splines in the shift crank. I could not make the prop shaft change directions with the shift shaft. So I pulled the shift shaft to inspect. I cannot see the splines in the crank with a light looking into the shift shaft cavity. I think the shift spool has shifted along with the shift crank, and the crank splines are no longer aligned to the shift shaft cavity to where I can re-insert the shift shaft.

Q-Can someone verify I am on the right track..
Q-Is there a way to get the shift crank back in alignment to where I can re-insert the shift shaft without pulling the drive and prop shaft and all of the internals of the lower as the manual shows?
Q-What is my best option for repairs here, estimated costs?
Q-Should I just purchase a new lower and sell this lower on eBay?

Need help!

Re: Shift shaft issues

Welcome to iboats...

If it was shifting fine before you did the job, but is not after you did it, the problem is not in the lower, you just don't quite undersatand how the clutch dog works.

Reinstall your shift shaft (how on earth did you get it out without the tool???)

1. turn the drive shaft clockwise while turning the shift shaft clockwise until the proper starts to turn. This is fwd gear.
2. After the propeller starts turning clockwise, stop turning the driveshaft and shift shaft, now try to turn the propeller counterclockwise only, you shouldn't be able to. If you can then keep on turning that driveshaft and shiftshaft until the propeller locks.
3. Use a bungie cord and grab the prop with 1 eye, with the other wrap the prop and hook it to the anti cav plate so your putting pressure on the prop in a counterclockwise fashion, Now you are locked in fwd gear.
4. reinstall the drive and just use 2 bolts. Have a buddy jump in the boat and while you are turning the prop, have him shift the boat into neutral first, then reverse, and see if that does it.
5. the alpha drives are not meant to be shifted unless the driveshaft is turning, you can get around it to a degree if the engine is off and you are turning the propshaft while shifting.

Re: Shift shaft issues

All of what Jason said +...

The Mercruiser stern drive units don't have a detent or positive feel to being in gear (forward or neutral). If you don't get it POSITIVELY in forward you'll end up with exactly what you're got. I do it a little differently to Jason, but the end result is the same. I turn the shift shaft CW while turning the prop CCW. That puts it positively in forward, and from that point on, if the prop move CW, I start again. I slide the lower up and if it doesn't go straight up all the way (it rarely does) I give the prop a slight turn CCW. Never had a problem....

Chris.......

Re: Shift shaft issues

3. Use a bungie cord and grab the prop with 1 eye, with the other wrap the prop and hook it to the anti cav plate so your putting pressure on the prop in a counterclockwise fashion, Now you are locked in fwd gear.

Click to expand...

Ayuh,... I Totally Agree with that,...

Tension on the propshaft HOLDS it in gear...
Otherwise, it always slips into neutral when you least expect it,...

Re: Shift shaft issues

lemooreace said:

Installed lower (not shifting), dropped unit, checked fwd gear again, installed, (still no shifting), tried this four times.

Click to expand...

It sounds as simple as you forgot to install the washer as indicated in the picture below: