Alpha 1 Gen 1 - Teardown - Need Advice

[theorifice]

Hi all,
First time doing work on the outdrive and noticed a few things that I'd like to get advice on. The boat is a 1987 with dual sterndrive (Carver Santego 30). I haven't a clue on the service history. The engines run great but was very hard to get into gear last year. I'm getting a bit low on time to get the boat ready for launch and looking to do just enough to get through the season without catastrophe. Expecting to

Initial inspection of shift cables by removing lower shift cable from bracket and shifting by hand showed high friction on the port side and medium friction on the starboard side.

Plan is to pull both drives, replace shift cables and impellers, inspect gimbal bearings and all bellows.

So far I'm into the starboard side.

* Welch plug missing. I'm doing the lower shift cable anyways. Anything else I might need to look at?

* trim ram pivots nearest transom are really stiff. Do the bushings to replaced or lubricated or are they meant to be tight? Seeing other videos, it looks like the rams could move freely.

* There's some amount of metal shavings on the magnetic drain plug. Is this a reasonable amount?


* There was a lot of grease on the inside of the drive shaft bellows. It looks like orings on the shaft were missing as we pulled out. I need to confirm they're not still in channel.



* Scoring on lower drive shaft near the water pump and near the splines


* Slight vibration when turning the lower shaft by hand. There is some end play and if I take up the end by pulling on the shaft, the vibration goes mostly away. (

)

* One of the waterpump bolts (nearest shift shaft) had a lot of corrosion. Is this a sign of another problem? Is it possibly due to the missing welch plug? Should I replace anything?


* The waterpump gasket was kind of fused to the waterpump. It looks like the plastic of the waterpump is slightly melted that is closest to the impeller. Is this an issue?


Thanks all!

 

[dubs283]

Are you referring to the welch plug on the side of the driveshaft housing for the shift slide cavity? If so, clean out the cavity and install a new one, they are available from merc

Water pump housing fastener has most likely been replaced with a ferrous nut. OEM is chrome plated brass, could get away with stainless but you risk galling.

Shavings on the magnetic drain plug is common, a bit much in this case but given the vintage/unknown service history I wouldn't worry too much at this point

Given the unknown service history it's in your best interest to start over completely. Full bellows including water passage hose and trim senders. Check engine alignments, grease couplers, inspect/replace gimbal bearings. Pressure test both drives, reseal as necessary. Replace both sea water pumps, base assys and gaskets. New gear lube in both drives

It's possible the port drive is counter rotated, keep this in mind when pulling the drive. If it is counter rotated the drive needs to be in reverse gear to properly remove

 

[theorifice]

Thanks for the info. I finished replacing the impeller, shift cables, and upper shift shaft bushings and installing the missing welch plug. I replaced the corroded nut and washer as well. Everything went pretty smoothly in reassembly and the drives are back on the stern.

I did note that the driveshaft housing lower seal (in the upper housing) were in poor shape on both port and starboard drives. I didn't have replacement parts on hand at the time and I ran out of time to get parts to replace. They seem to be fairly easy service items.

What is the risk of leaving these seals in their current state for a season? I'm on a very very tight timeline to get the boat back in the water as the storage facility needs all boats out VERY soon and I need to be ready.

 

[dubs283]

Those seals aren't even close to being okay. I wouldn't trust them for a minute of use let alone a full season. Based on the picture I'd guess both drives are in need of complete reseals

Did you pressure test the drives before filling with lube?

Don S. had a signature that said, "Why is there never enough time to do the job right the first time but always time to do it again?"

 

[nola mike]

Those seals aren't even close to being okay. I wouldn't trust them for a minute of use let alone a full season. Based on the picture I'd guess both drives are in need of complete reseals

Did you pressure test the drives before filling with lube?

Don S. had a signature that said, "Why is there never enough time to do the job right the first time but always time to do it again?"

Agreed. Those seals need replaced. Water gets in the cavity, rusts and pits shaft. Then you have a lot more work. Also hope you replaced that lower pump base as well as the impeller. And for sure pressure test the drive.

 

[theorifice]

I haven't replaced the water pump bases. There was some wear on the water pump bases and some evidence of overheating but did not look severe. If I had parts on hand, I would have replaced the bases and waterpump housings. The impellers were replaced though the old ones looked ok.

I'm assuming that the current condition of the drives is the condition they have been in for a few years as I know the previous owner had not done any maintenance items. The gear oil reservoirs had maintained their levels throughout the previous season so I'm not too concerned about losing oil. For the lower driveshaft seal, it already looks like the shaft is a bit corroded but not too severely. AFAIK - that seal's function is to prevent water from intruding towards the upper seal that seals in the gear oil.

Other than the lower shaft seal, most of the drive looked OK IMO. For sure pressure testing will be necessary. At this point though, I don't think I will have time to complete any additional repairs beyond the seals that are easy to access.

I'd like to get through the season (freshwater) - pull the drives for next winter and perform deeper maintenance including pressure testing.

I'm going to do some thinking about the tradeoffs here. I'm primarily concerned that I don't have adequate time before launch.

 

[Scott06]

I'd like to get through the season (freshwater) - pull the drives for next winter and perform deeper maintenance including pressure testing.

I'm going to do some thinking about the tradeoffs here. I'm primarily concerned that I don't have adequate time before launch.

you wont get through the season with those seals.

If you do decide to press on check your lube frequently.

To pop those lower seal out of the upper is an afternoon of work...

 

[Bt Doctur]

If the pump base is melted even slightly you have overheated and the base needs replacing

 

[ddrieck]

If either of drives have overheated and melted the impeller housing you should also check the upper housing for melting and damage. Plastic Housing where the the water pipe mates and held in place in the upper drive housing.
On the top of the lower unit input shaft I see there is not an o-ring. No need to install one as Mercruiser put out a bulletin years ago to not use that o-ring any longer. SEI (Sterndrive Engineering) does not even cut that o-ring groove into there shafts.
As for those seals, no way in "HE double hockey sticks would I personally put my boat in the water for a an hour let alone an entire season. Better off replacing them now and not have issues later on.

 

[theorifice]

Thanks all for the input. I've ordered parts and will hope for good weather to get the boat in the water next week. I completely agree that it is not a lot of time to pull the drives and replace the seals and water pump housings.

The impeller kit I contained an o-ring that fit the shaft. I put that o-ring on the shaft. Is there any harm in having it there? What was the reason behind not installing the o-ring?

On both port and starboard, the water pocket housing looks in good shape so replacement shouldn't be necessary.

 

[ddrieck]

Thanks all for the input. I've ordered parts and will hope for good weather to get the boat in the water next week. I completely agree that it is not a lot of time to pull the drives and replace the seals and water pump housings.

The impeller kit I contained an o-ring that fit the shaft. I put that o-ring on the shaft. Is there any harm in having it there? What was the reason behind not installing the o-ring?

On both port and starboard, the water pocket housing looks in good shape so replacement shouldn't be necessary.

Can't remember off hand why Mercruiser put out that bullition back in the day and what issue it solved.

 

[theorifice]

Should I worry about replacing the shift shaft bushing and seal on the lower unit? It's not totally clear what parts are necessary. From the following part stack (from https://www.mercruiserparts.com/bam/subassembly/30870/2203/110):



I'm thinking:

• 47 - reuse
• 48 - https://nuwavemarine.com/uncategorized-mercury-parts/oem-mercruiser-o-ring-e-j-25-25439/
• 49, 50, 51 - https://nuwavemarine.com/uncategori...iser-shift-shaft-housing-bushing-23-77631a-2/
• 52 - reuse

Port:
Starboard:

 

[Scott06]

Can't remember off hand why Mercruiser put out that bullition back in the day and what issue it solved.

I think the oring on the shaft tended to mess up the shaft seal when reassembling , so they dropped it

 

[nola mike]

you wont get through the season with those seals.

If you do decide to press on check your lube frequently.

To pop those lower seal out of the upper is an afternoon of work...

That seal keeps water out of the drive shaft area. Drive shaft will rust over time but won't lose lube. Just replacing the lower seal is easy, doesn't require removing the input shaft. Upper is more work

Can't remember off hand why Mercruiser put out that bullition back in the day and what issue it solved.

The o-ring would get caught in that lower seal and let water in.

Should I worry about replacing the shift shaft bushing and seal on the lower unit? It's not totally clear what parts are necessary. From the following part stack (from

That bushing is a pita. Pressure test your drive. If not leaking leave it. If it is, get the special tool

 

[theorifice]

That seal keeps water out of the drive shaft area. Drive shaft will rust over time but won't lose lube. Just replacing the lower seal is easy, doesn't require removing the input shaft. Upper is more work

That's what I was thinking based on my understanding of the seals in place. The shaft looks like it's been minimally corroded already but not catastrophically so. Definitely interesting spectrum of responses here!

The o-ring would get caught in that lower seal and let water in.

That makes sense. I can imagine without it the groove could catch the seal and tear it too. Installation is a bit sketchy as it stands especially with a single set of hands! I used my phone in selfie mode to give me a visual from the bottom:

That bushing is a pita. Pressure test your drive. If not leaking leave it. If it is, get the special tool

Thanks for the heads up. It looks like a reasonably easy bushing to remove especially with the tool. Is it commonly seized?

 

[theorifice]

Has anyone ever used nylon lower shift shaft bushings?

https://www.amazon.com/Replacement-Mercruiser-23-30617A2-Generation-1972-1990/dp/B0752ZBSK9/