Shift shaft has 12 degrees of play.

[Steelguitarman]

I own a 1989 mercruiser 305 with an alpha 1 gen 1 sterndrive.

For the last 3 years, I've been dealing with a shift issue that would remain even after following the manual to a T. However, I alway got by making minor adjustments to a sweet spot.

Last season, that sweet spot was gone. To describe the symptoms, I could go into forward fine, and reverse fine. But one or the other I could not get out of, usually reverse. And when it would happen, I would basically need to shift slightly into forward gear to get it to go into neutral.

Too much slack is in the system and it would not trip the interruper switch.

Turns out my upper shift cable is worn, 3 3/8 in total travel, and lower shift cable is just under 9/16 in. Which had been, even when I replaced the cable 3 years ago, maybe a bit less then.

I pull the drive and cut the degrees template from the manual, and sure enough, the shift spool assembly has 12 degrees of play.

So my question is, what exactly on this system wears, is it the shift spool, the shift crank, or something with the shift shaft?

How do I check these?

Is this something I will be able to do?

I am fairly handy and have made my own tools before working on other outboards, however, I've never cracked into a mercruiser sterndrive.

There is a retaining ring that looks kinda suspicious, especially if it's seized into place. What are some of the special tools?

Is it more cost effective to buy a new sei lower unit(possibly upper too). This outdrive had the wrong gears installed during a 2009 rebuild(long before me). The motor runs great and I've never had any problems besides this shifting issue. Maybe it's something I tear down and see what's worn?

Thank you in advance, wanting to get her ready for summer trolling on erie!

 

[Steelguitarman]

Update: just tore it down a bit more. I was able to isolate some of the play.
With the upper and lower separated, the spool had between 9.5 and 10 degrees of play.

The rest came from The slop with the shift shaft and upper housing.(please see picture)

This may be completely normal and accounts for the slop. But it's something that seems excessive, is this a replaceable bushing here?

 

[Steelguitarman]

Hello,

I watched a few videos and feel I can handle this task. Many of the tools I can make, or buy as they are not very expensive.

My intermediate shift shaft goes from about 10 to 12:30.

So this would warrent a shift spool and shift crank replacements?

What other things should I look out for?

The lower is an sei(I believe) that was replaced 15 years ago by the previous owner.

Would neglect or not changing the oil cause wear to either one of these parts? It just seems like alot considering the engine is low hours if it is correct. Or, are the sei parts not holding up well?

Alot of the replacement parts I can find are SEI. Is it worth paying alittle bit more for the oem? That's usually what I do, but in some causes it just not necessarily.

Just need alittle guidance on how to approach this issue and move forward,

Thanks

 

[Fun Times]

Have you seen the following video yet?

 

[Steelguitarman]

Have you seen the following video yet?

Yes, I followed that purcedure and used that template from the manual to determine my initial play.

I've isolated the play and they majority of it is in the gearcase. My intermediate shift shaft has a small amount of play, but not much.

 

[Fun Times]

In this case you might want to stay with SEI parts only because I do believe (not 100% certain though) over the years Merc had changed a design to the shift spool and it "might" tend to create a different challenge for installation purposes without proper documentation paperwork to follow along with should it be called for...I'd have to think SEI may not had changed anything so easier to install should that be an actual case...Plus they do have their own tech forum you can post on and a few of their techs generally tend to respond a day or 2 later it seems if desired for additional help.

 

[Steelguitarman]

In this case you might want to stay with SEI parts only because I do believe (not 100% certain though) over the years Merc had changed a design to the shift spool and it "might" tend to create a different challenge for installation purposes without proper documentation paperwork to follow along with should it be called for...I'd have to think SEI may not had changed anything so easier to install should that be an actual case...Plus they do have their own tech forum you can post on and a few of their techs generally tend to respond a day or 2 later it seems if desired for additional help.

Thanks for the information!

 

[Steelguitarman]

So I just want to make sure I'm capable 9f doing this. One thing I read in the manual is about putting preload on certain components.

Is this necessary if I'm not replacing any gears or bearings?

 

[dubs283]

I've measured the free play in the shift shaft on a few Alpha One/MC-1 drives and I've only seen one out of spec. That one drive came off an older boat with an oem/original style (threads into the fwd side of the bell housing and core cut to length) lower shift cable. The shift adjustment had been re adjusted many times over the years and not properly so as to cause excessive wear in most components of the shift system.

The picture in post #2 showing the shift shaft seal is not mercruiser. Can't say if it's SEI as I've never dug that far into one. No clue if the shift components in the gear case are compatible between the two brands.

If the spool/crank assy is worn to the point of needing replaced there may be an issue with the clutch dog/gear face teeth as well. Only way to know is to disassemble and inspect.

Certainly a doable job, you'll need at least one special tool, maybe two if you want the job to go smooth/efficient. An oem manual will aid greatly as well.

Might want to consult SEI to see about part availability if indeed the unit is SEI. Iirc new lowers from them are about $1000

 

[Steelguitarman]

The picture in post #2 showing the shift shaft seal is not mercruiser. Can't say if it's SEI as I've never dug that far into one. No clue if the shift components in the gear case are compatible between the two brands.

That picture is showing the intermediate shift lever bushing(a stainless steel bushing about .61inches ID. Which is located in the upper of the outdrive.

Whereas the shift shaft seal in located in the lower.
That bushing seemed to be wore out,however, looking at others, it looks like it's not supposed to be a snug fit.

There is an "SE" that was cast in the upper. No markings on the lower.

I assumed is was sei, but I could see it be some other brand.
I'm prepared to tear this down and see what it needs. Then decide if I'll buy the parts or a whole new lower.

The shift cable was adjusted wrong when I got it. It wouldn't suprize me if it caused premature wear. I've prepared for the worse.

However, there is many parts that are wore in this system. The intermediate shift shaft itself (the spines) as a few degrees of play, the upper shift cable is worn, and the drive itself makes up for the rest.

 

[nola mike]

That picture is showing the intermediate shift lever bushing(a stainless steel bushing about .61inches ID. Which is located in the upper of the outdrive.

Whereas the shift shaft seal in located in the lower.
That bushing seemed to be wore out,however, looking at others, it looks like it's not supposed to be a snug fit.

There is an "SE" that was cast in the upper. No markings on the lower.

I assumed is was sei, but I could see it be some other brand.
I'm prepared to tear this down and see what it needs. Then decide if I'll buy the parts or a whole new lower.

The shift cable was adjusted wrong when I got it. It wouldn't suprize me if it caused premature wear. I've prepared for the worse.

However, there is many parts that are wore in this system. The intermediate shift shaft itself (the spines) as a few degrees of play, the upper shift cable is worn, and the drive itself makes up for the rest.

Also check that the shift shoe fits the intermediate shaft snuggly. That can be a source of play as well

 

[Steelguitarman]

Wasn't aware of this! Thank you.
I assume the brass intermediate shaft would wear and not the stainless steel shoe of the shoe?

 

[Steelguitarman]

I was able to tear down the lower unit tonight.

Bearings look okay, gears look okay.
Propshaft had about .0025 in of play. I read the tollerance for that bearing is .003in. Should I replace this while its apart and when I replace seal?

My findind on the shift spool have not been conclusive.
See the first image, it's just a witness mark. No visible wear. Maybe just the tiniest groves.


The crank does show some wear. While it does not seem excessive, it is worn some.

The lower half that spins on the stud in the gear case has a bit of wear and feels sloppy. But it could be normal.


The bar that goes through the dog clutch has a small bit of play and is ever so slightly worn, is this normal?


I'm having a hard time seeing all of the play in just these parts here..

The intermediate shift cable spines had some slop.. I order a new one of those. However, it wasn't much alone. I could see this having a few degrees of play. With that said, how many degrees of play should a new system have?

Unless the wear of all the parts combined leads up greater than what they seem.

How would you move forward? Is there something I am missing or overlooked?

Thanks

 

[Fun Times]

Just wondering, how is it going @Steelguitarman ? please keep this one updated.

Think this was what i was trying to remember with the info above of post number 6,

SHIFT SPOOL FOR ALPHA ONE & ALPHA GEN II | Service Bulletin | Crowley Marine

08-JUN-2000 - Manufacturer Service Bulletin: SHIFT SPOOL FOR ALPHA ONE & ALPHA GEN II

www.crowleymarine.com

 

[Steelguitarman]

@Fun Times ,
Hey, I'm getting it back together now. Unfortunately the carrier had a small crank in it(possibly from pulling?

The cast material seemed to be fairly poor quality and oil soaked, so instead of trying to tig weld it, I opted for a new carrier.
I have all the parts and just need to get a chance to press the bearing and gear into the new carrier.

As before, I had just at 12 degrees of play.
The most play was found to be in the bronze intermediate shift shaft splines.

Small amount of wear was found in the cross Pin and shift crank, however, it really didn't amount to much. Just a few thousands thicker on either part.

So in reality, I likely could have gotten away with just replacing the intermediate shaft, but it was a good learning experience to tear down and replace the seals.

I now have at about 8 to 8 1/2 degrees of play(without carrierinstalled, if that matters). Hopefully that's enough. I also found the stainless upper shift shaft shoe to be alittle sloppy, so I bent that in the vise to give a snug fit

At the top end, I've replaced both upper control cables and throughly broke down and cleaned the controller.

My throw has improved, but is still over the tollerance by about 1/16 an inch at 3 3/16.

When I put the cable in the hole with the shorter throw, it came up 1/16 an in below the bottom tollerance of 2 7/8 in.

However, the new cable has much less play, fingers are crossed that it shifts well on land and the water.

 

[Fun Times]

Awesome details of the work being both found and done, sure hope it all works out well for you in the end… thanks for sharing, great learning experience for all. Good luck and don’t be shy to update again.