Alpha One Gen II metal bits and oil on lower unit water pump casing

Jiboat

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This is my first post, and I've looked and searched, but haven't found an adequate answer. My apologies if this has been covered, but I couldn't find anything. So, on to my problem:

A week ago, I launched the boat at the lake, and while getting ready to take a spin, I noticed oil on the water. Not a ton, but enough to be concerning. I immediately took the boat back out and noticed gear oil emerging from the front weep hole on the lower unit (1996 Mercruiser Alpha one, Gen 2 with gear oil reservoir in engine bay). I took the lower unit off (leaving the upper attached to the boat), since I knew that I would be needing to replace the water pump for regular maintenance, anyhow. Once I split the lower from the upper, I pulled it down to remove it, and I'd estimate about 1/2 a cup of oil came from the upper drive shaft spline area. This is my first question: is this normal, and perhaps I didn't drain the oil completely? I am assuming that the splines are covered in oil, and it may have taken a while for the oil to drain from the reservoir.

Second question, and probably more important: After I pulled the lower for inspection, I noticed that the shift shaft area (which I thought the leak was likely from the shift shaft seal) was covered with older oil. However, the water pump casing, a little bit of the drive shaft, and inside of the upper unit were also covered with blackened gear oil. This oil appeared to have been there for a while, but it's hard to tell. Even more concerning was that along with this residue, there was also a significant amount of metal grit (sticks to a magnet) mixed in with this oil. I have attached a photo of the lower unit as it currently stands. (You can see where I wiped the impeller housing.)

The fresh oil seen on the pics is the remainder of what drained from the upper when I split the lower from the upper, but the water tube was covered with black soot. I recently fixed some carburetor issues, so there may have been some rich exhaust that caused this.

Regardless, I am usually under the assumption that metal grit is bad, and I didn't think this area should have such a significant amount of oil residue. I haven't done any further work yet. Any thoughts? I'm planning to pressure test the lower to see if oil may be coming from the shift shaft seal, but could this oil have traveled to the places seen on the photo? The ferrous metal is possibly a bigger concern.

Also, no water in the oil, from what I could tell, and I didn't yet find grit in the oil that was drained, but I'll report back if I do.

Thank you!
 

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alldodge

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You should never see that kind of metal, and looking at the upper portion of the drive shaft it shows the drive was been running dry. The drive shaft is shinny

The drive should be pulled completely at the end of every season or at least every other. Lube drained, alignment checked and fresh lube pumped back in from the bottom of the drive and out the top.

The upper should drain fully out thru the bottom when the plug is removed. Only reason if it didn't drain is some of the metal or other crud is blocking the pass thru hole

Looks like your going to need to take both halves apart and inspect for damage
 

Jiboat

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I've just taken the upper off, also. Will have to tear into it to see what's what. I bought this boat late last summer, and the reservoir hasn't run lower than 1/2" below the fill mark. However, I did fill it to the mark and it just recently dropped again to that mark. I ran a quick soapwater pressure test on the lower, and no bubbles, but I haven't kept pressure on it to fully test it. As for the upper, the damage is yet to be uncovered.

Do you have any suggestions on what to be on the lookout for?

I also snapped a shot of the bellows/gimbal. Should there be so much grease there? I've worked on plenty of cars, outboards, a various small motors, but this is my first attempt at an I/O. I'm now looking for the service manual I swear that I downloaded last year...

Thanks!
 

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alldodge

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To pressure test, it should be done with no more then 10 psi, and doing a vacuum is also good

Normally the only metal you see is on the drain plug magnet and its just dust, no shavings or chips. Take the top cap off the upper drive and see what the gears and bearings look like
 

Searay205

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problem with remote lube oil reservoirs is over time if not changed regularly the get a very thick gooo on the bottom. That gooo holds the level switch tricking it that it has fluid.
 

harringtondav

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My thoughts:
Unless you have you drive completely trimmed down when you drain it, there is always a little residual lube. Some pools in the driveshaft bearings in the forward part of the "snout". Also the lube transfer hole in the upper case breaks out above the lower drive shaft seals, leaving a little lube

The metallic grit on the water pump housing most likely came through the exhaust cooling water. It could be loose rust from the engine's cast iron cooling jacket or the exhaust manifolds. I've never seen this in my '96 Alpha II, but I've read about it here. Unless you are have a catastrophic melt down in the upper housing, it's probably from the engine somewhere. If so probably harmless, but worth watching.

Lube in the water around your boat is a sure sign of bad outdrive seals somewhere, unless you engine is leaking oil through the valve stem seals. But your boat would smoke like a two-stoke.

No sugar coating the fix. You need to tear down you drive and install upper and lower housing seal kits. When you're doing this you will spot any distressed gears or bearings.

BTW, your lower gear case looks pretty darn good for 24 yrs old. Original or replaced sometime?
 

Rick Stephens

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First thing to do is pull the top cap of the upper gear case. See what you have inside.

hen you pull a lower with a lube bottle attached isn’t it going to leak some into the drive?
 

harringtondav

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hen you pull a lower with a lube bottle attached isn’t it going to leak some into the drive?

OP mention he drained the drive. If he removed the lube reservoir cap, the bottle should have drained. But if the cap was left tight on the bottle, the check valve will slowly let air enter and the remaining lube in the reservoir will dribble into the upper.
 

Jiboat

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OP mention he drained the drive. If he removed the lube reservoir cap, the bottle should have drained. But if the cap was left tight on the bottle, the check valve will slowly let air enter and the remaining lube in the reservoir will dribble into the upper.

This. I did not remove the cap before draining. I thought about this afterwards, but I did leave it drain for a good hour, so I thought it should have drained completely. Maybe I was wrong. Either way, I drained it in the trailer position, and when I removed the rams and dropped the upper, another bit (1/4 cup?) of gear oil came out. I'm thinking it was residual left in the gear case in the "up" position.

I have also attached a couple pics of the gears and cover after I popped the top last night. There appear to be some flecks on the left-hand side of the top gear - could be metal, or could be corrosion that dropped in when I cracked it open? It was getting late and I didn't swab it to see last night. The oil inside and on the top had no flecks, and was clear and clean. If it is metal, could this be from bearings? The gears, themselves look good.

As far as the oil slick on the water I mentioned previously, I just remembered that I did see a very slight patch of oil several times when starting the boat after I first got it, but I figured this was unburnt fuel due to the carb issue. I don't recall seeing much of a sheen on the water after the carb fix. Never recall seeing a spot on the driveway. But, food for thought.

Also, another possible clue: When turning hard right, the outdrive made a dull fast clicking sound the last couple times I took it out. I don't know if this is normal - I thought it could have been from the universal joints at their turn limit and didn't think much of it, since I usually don't make such hard turns (I made the turns to pick up a skier). The noise want away when I straightened out, and really only occurred at harder turns at slow-moderate speed.
 

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Jiboat

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problem with remote lube oil reservoirs is over time if not changed regularly the get a very thick gooo on the bottom. That gooo holds the level switch tricking it that it has fluid.

I did notice this goo last year, and I removed the reservoir and cleaned it out this spring, before adding fresh gear oil.
 

Jiboat

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My thoughts:
Unless you have you drive completely trimmed down when you drain it, there is always a little residual lube. Some pools in the driveshaft bearings in the forward part of the "snout". Also the lube transfer hole in the upper case breaks out above the lower drive shaft seals, leaving a little lube

The metallic grit on the water pump housing most likely came through the exhaust cooling water. It could be loose rust from the engine's cast iron cooling jacket or the exhaust manifolds. I've never seen this in my '96 Alpha II, but I've read about it here. Unless you are have a catastrophic melt down in the upper housing, it's probably from the engine somewhere. If so probably harmless, but worth watching.

Lube in the water around your boat is a sure sign of bad outdrive seals somewhere, unless you engine is leaking oil through the valve stem seals. But your boat would smoke like a two-stoke.

No sugar coating the fix. You need to tear down you drive and install upper and lower housing seal kits. When you're doing this you will spot any distressed gears or bearings.

BTW, your lower gear case looks pretty darn good for 24 yrs old. Original or replaced sometime?

The outdrive is original, to my knowledge. It's been a freshwater boat all its life, and I don't think it's ever been docked.

I'm liking the idea of this being metal from the exhaust - but does the exhaust circle around in that cavity? Could all the oil reside in there also be due to the bad carb and fuel mixture from the past?
 

alldodge

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Think those flakes on the gear is from the top cap being removed and they fell inside as it was removed
 

Jiboat

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I forgot to mention that I checked all of the gear oil that I drained, and didn't find a single speck of metal or sign of water intrusion. I'm presently thinking that I agree that the flecks on the gears was residue from the top cap, and that the metal flakes (not in the gear oil, but in the lower cavities) were from the exhaust. But what about all that oily residue? Could that be from the fuel/carb problem, and would the exhaust gases get into that cavity to cause it? I'm not certain how the flow occurs in there. Or, perhaps I've had a small seal leak for some time and just haven't noticed it.
 

harringtondav

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Your top end gears look great, as well at the bearing. I'd bet the rest of your drive's innards are fine.

The most of the exhaust exits through the lower housing around the lower drive shaft and water pump once you throttle up.

Now that you've mentioned a possible carb issue, the sheen in the water could be gasoline, but you'd be having performance issues from a rich mixture, plus smoke and a smudge around your outside transom.

Since you mention gear oil dribbling from the water pump drain hole, and a fairly rapid loss of lube from the reservoir, I suspect the two seals in the upper housing that seal the lower drive shaft are leaking lube into the lower housing cavity.

Depending on annual hours of use, this drive will need a re-seal job every ten years. Given the good appearance of your drive, the seals may be original and ready for replacement. Only two special tools are absolutely needed for a re-seal. The spanners for the drive shaft assembly retainer, and for the prop shaft seal carrier. http://www.boatinfo.no/lib/mercruiser/manuals/mercruiser17.html#/0 will show you the process and required tools.

The clicking sound isn't normal. When you pull the drive you'll be able to check the usual suspects: Bad gimbal bearing or bad U joints.
 

Jiboat

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Thanks again!

I replaced the carb, and that fixed the carb issue, but I did have gas in the water, along with the black streaks on the back of the boat. However, that problem should be gone for now. As for the upper housing seals, I couldn't get the boatinfo.no link provided to work properly. Am I missing something? I've got a manual that I downloaded from https://www.downloadboatmanuals.com/motors/mercury/mercury-mercruiser-service-manual/

Are you talking about the seal at the bottom of the upper gear case, where the drive shaft from the lower unit enters? If I'm not mistaken, I think read previously that this seal needs to be removed from the top end.
 

Rick Stephens

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Next thing is do a compression check and find out first the base condition of your motor, and second, if there is something obvious pushing metal and oil/carbon fouling into the exhaust. Do the compression test warmed up. Pull all the plugs and run five compression cycles for each cylinder. Inspect spark plugs as well. I've never seen metal like that. Rust, yeah. Seems most likely something is being eaten.
 

Searay205

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Metal i see is iron. usually chunks heavily rusted. I like to **** saturday when i saw one thicker than what my engine block or manifold are. I realized it is from where the flex hoses connects to the end of the manifold. anyway got the message new manifolds going on period. Not worth tearing up $8K mpi engine for $2K in manifolds. your metal looks like machine or grinding. Most metal goes out the prop exhaust why would it hang around there, flooded with water... That is where I found mine was looking in where the propeller mounts.
 

Jiboat

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So I took a good wipe of the grit on top of the impeller housing and attached a photo of what stuck to a magnet. I am feeling a bit relieved, as this really looks like flakes of rust - probably from the manifold? I actually planned to do a compression test for general knowledge of the state of the engine, but at least for now, I think these flakes are a better sign that it's more "normal".

I'm wondering if the excessive unburnt fuel from the bad carb had gummed things up in the lower unit, to the point where these flakes and grit were attracted to the sludge. Hopefully, in the next couple days, I'll have some time to do a full pressure test of the upper and lower, and get to the bottom of this.
 

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harringtondav

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Thanks again!

Are you talking about the seal at the bottom of the upper gear case, where the drive shaft from the lower unit enters? If I'm not mistaken, I think read previously that this seal needs to be removed from the top end.

Any version of a Merc manual #17 will work. Online or paper. Don't trust others.

There are two back to back seals in the upper housing below the driven pinion. The drive shaft assembly must be removed to lift the upper drive shaft and this pinion (shown under the top cover in your pic) out. The seals are punched up and out from the bottom of the upper gear case.

Do the pressure and vacuum tests to verify first. But with lube leaking from the lower housing my bet.is these seals need replacement. And if you're in that deep you may as well re-seal the whole thing and boat care free for another ten yrs.
 
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