1983 Mercruiser Sterndrive - R

[Iroc-Sea]

Hey there - have an '83 Cobia Sportster with a Merc 470 and a R Sterndrive. Despite the reputation of the 470, the engine and boat have served me well over the past 12 years. However last season was the first year that I left it docked all season. No issues through the season - ran strong until I took her out of the water in early November. When I drained the drive lube oil at the end of the season, water and mix of dark lube oil came out. I refilled the lube oil for the winter and level is still good/hasn't leaked out.

I'm assuming there is a leak and water had gotten into the drive as it sat in the water for several months. Not sure what the extent of the damage to the drive is and I have not worked on outdrives before I am very mechanically inclined and wouldn't mind a pre-season project. I just got a copy of the service manual and plan to begin studying it.

I removed the top cover of the drive to see how the top bearing looked. Attached are the pictures. You can see the remnants of the grey oil and the fresh new oil below.

Looking for any tips pointers or advice anyone might have! Figure I need to start by pulling the drive and pressure testing to find the leak(s).

 

[Fun Times]

Hey there - looking for a Mercruiser service manual (#6) for my 1983 type R Sterndrive. I know I found it on here over a decade ago when I bought the boat but the link to that site is down. If anyone has a copy or has any tips please let me know. Thanks!

Think you'd have to pay for this one to fully work Mercruiser Service Manual 6 Outdrives R/MR/Alpha One/Alpha SS | Paint | Nut (Hardware) (scribd.com)

Possibly look a private message from @Bt Doctur as he may have one on file should this one not work for you, Boatinfo - Mercruiser Service Manual nr. 6 - 1983-1990 - R, MR, Alpha One & Alpha One SS Sterndrives

Also check EBay for an actual used usually lower cost book..., Mercruiser Service Manual Number 6 Sterndrive Units | eBay

 

[Iroc-Sea]

Thanks, found a copy!

Think you'd have to pay for this one to fully work Mercruiser Service Manual 6 Outdrives R/MR/Alpha One/Alpha SS | Paint | Nut (Hardware) (scribd.com)

Possibly look a private message from @Bt Doctur as he may have one on file should this one not work for you, Boatinfo - Mercruiser Service Manual nr. 6 - 1983-1990 - R, MR, Alpha One & Alpha One SS Sterndrives

Also check EBay for an actual used usually lower cost book..., Mercruiser Service Manual Number 6 Sterndrive Units | eBay

 

[Iroc-Sea]

Bump...

any thoughts/prognosis on what I’m seeing in the top case or with the water intrusion? Bellows possible?

 

[Bt Doctur]

you have to clean all that out first. I have flushed the drives with diesel pumped in and run for about a minute or so, drain and repeat.Option 2 is to remove the top gears and clean everything

 

[MagKarl]

I'd also vote for diesel flushes if it were mine.

 

[Scott06]

As mentioned clean it out then pressure test to find leaks. Given the age of the drive i would suspect it is due for a complete seal replacement. Given moisture intrusion you want to check bearings fir signs if corrosion and wear

 

[nola mike]

It'll be obvious if it's bellows when you pull the drive. Probably not though; water through the bellows would end up in the boat (possible with small leak that you didn't notice if the bilge pump was keeping up). Also possible if a lot of water got in the boat and leaked backwards into bellows

 

[Iroc-Sea]

Thanks guys! Appreciate the tips. Rookie question, pump the diesel in just like lube oil? What would you say, 30 seconds in forward 30 on reverse light throttle?

The drive was resealed back in 2014. Hoping it’s something easily accessible. Will check out the bellows when I pull the drive - also plan to replace the shift cable, trim sender (gauge never worked) and impeller/water pump. Any other maintenance items I should get too while drive is off? Thanks again!

 

[nola mike]

You won't be able to pump diesel in from the bottom. Either through the top, or pour in from the top cover. I know people do it, but man I'd be nervous running a solvent on my bearings. I certainly wouldn't give it any throttle. Fwd/reverse probably doesn't matter much, everything but the prop shaft is spinning in neutral anyway. If it's me, I would just fill it with the diesel, let it sit, turn by hand a bit and drain. Depending on what it looked like after that, I might just fill with lube, run it for a bit and then just change it sooner than normal.

 

[achris]

You won't be able to pump diesel in from the bottom. Either through the top, or pour in from the top cover. I know people do it, but man I'd be nervous running a solvent on my bearings. I certainly wouldn't give it any throttle. Fwd/reverse probably doesn't matter much, everything but the prop shaft is spinning in neutral anyway. If it's me, I would just fill it with the diesel, let it sit, turn by hand a bit and drain. Depending on what it looked like after that, I might just fill with lube, run it for a bit and then just change it sooner than normal.

Without load, diesel is fine. It's quite 'oily' and isn't going to wash the bearings and run them without lube.

 

[Iroc-Sea]

update!

Pulled the drive today. I think the bellows look good, gimbal bearing spins freely. I attached some pictures for reference.

I flushed with diesel a few times. I didn’t reattach the drive and run it, I just let the diesel sit in the drive for a while and spun the u-joint by hand a few times before draining. You guys were right, it came clean and there doesn’t appear to be any visible damage / chewed gears. What’s concerning me is I’m pretty sure the prop shaft was spinning when I spun the u-joint initially (drive in forward and rotated clockwise). But then on the second flush, I noticed the prob shaft wasn’t spinning when I rotated the U-joint. Did I screw something up/de-couple something?

Hopefully will pressure test tomorrow. Let me know what you guys think of the pictures / if I should be concerned about prop shaft. I’ll be pulling the lower to do the water pump / impeller later this week.

 

[nola mike]

I don't think you could have screwed anything up, but it should turn the prop shaft unless you're in neutral. You tried moving the shift lever fwd/reverse and turning the input shaft, right?

 

[Iroc-Sea]

I don't think you could have screwed anything up, but it should turn the prop shaft unless you're in neutral. You tried moving the shift lever fwd/reverse and turning the input shaft, right?

I didn’t go into reverse I don’t think, maybe I inadvertently found neutral. Will play with it again tomorrow and report back. Thanks!

 

[achris]

Unlike outboards the shift spool is not detented. Just changing the angle of the drive is enough for it to move and the drive to drop in and out of gear. Have a look at my videos (link in my signature) on how to select forward when you go to put the drive back on.

 

[Iroc-Sea]

Well I must have been in neutral. When I move the shift shaft it engaged and prop spins shaft as it should.

On another note, I’m stumped again - I got the pressure test done today. With the drive together, it would not hold pressure. I could hear air coming out from the compartment that the drive shaft passes through. From there, I spilt the upper and lower. Pressure tested both separately and they held 15psi for two hours each! I don’t know where I was losing pressure from, or where water is getting into the lube oil. The only thing I could imagine is maybe the quad seal (o-ring sealing oil passage between upper and lower) wasn’t seated properly? Any other thoughts?

Anyway, replacing the impeller now but my kit didn’t come with the pump base. Mine looks a little shot so going to try to buy that separately.

Inside the impeller top housing it looks like something melted. The new housing is empty in that groove. Anyone ever see that before?

Thanks!

 

[Scott06]

How did you seal the vertical drive shaft in the upper to hold 15 psi ?wondering as i would like to do the same test of each half

 

[nola mike]

How did you seal the vertical drive shaft in the upper to hold 15 psi ?wondering as i would like to do the same test of each half

You don't need to except on the gen2. Need to seal the quad seal passages,I use a rubber stopper.

 

[achris]

...On another note, I’m stumped again - I got the pressure test done today. With the drive together, it would not hold pressure. I could hear air coming out from the compartment that the drive shaft passes through. From there, I spilt the upper and lower. Pressure tested both separately and they held 15psi for two hours each! I don’t know where I was losing pressure from, or where water is getting into the lube oil. The only thing I could imagine is maybe the quad seal (o-ring sealing oil passage between upper and lower) wasn’t seated properly? Any other thoughts?...

Only 2 possibilities. You left the quad ring out (or knocked it out of place)... Or, you put the o-ring on the driveshaft and it's holding the seal in the bottom of the drive-shaft housing (top box) open... Even if you have an o-ring groove in the shaft, DO NOT fit an o-ring to it... Later driveshafts came without the groove, for a reason!

 

[nola mike]

Or, you put the o-ring on the driveshaft and it's holding the seal in the bottom of the drive-shaft housing (top box) open...

Or you have/had bits of that o-ring leftover that someone else put on, and then it got shoved into the upper seal area when you put the drive back together (just had this scenario)