Gear oil leaking from water intake on Alpha one???

[idflyfisher]

OK. First off I am a complete noob and hack mechanic, but I have more time than money so I try to do as much as I can myself. I dropped the lower unit on my 4.3l mercruiser alpha gen+. and changed the impeller and the upper seals. I was having high engine temps and was losing small amounts of gear oil. The impeller did not look to bad but one of the seals in the seal carrier was damaged. After I changed the seals, new impeller and new impeller gaskets installed, I put the lower unit back on. Filled with gear oil and tested the motor. Even hotter. Dropped the lower unit to investigate. Turned out I did not have the water tube aligned and was getting no water to the thermostat housing. Put it all back together and gear oil leaked out of lower unit before ever reaching the vent hole. I was told I forgot the o ring . Dropped the lower unit again, O ring was present, but I replaced with a new one. While I was trying to put the lower unit back on I notice gear oil leaking from the water intake holes???????????? Can someone explain how I am getting gear oil in that part of the lower unit, and how to check/fix issue. At this point I am wishing I had just taken it to a shop and had them deal with it.

 

[ktbarrentine]

Re: Gear oil leaking from water intake on Alpha one???

As a "complete noob" it is HIGHLY recommended that you take the entire drive off of the boat to do maintenance such as impeller replacement (at least until you get the hang of how it all works). This gives you the advantage of being able to work things "on the bench" and actually be able to see how the things go back together (i.e., can see the water tube going into the upper drive, and vertical drive shaft going in past its seals, via looking into the exhaust port while reassembling the drive.
Also, you get to do all of your other recommended maintenance items while the drive is off, like inspecting/lubing U-joints, inspecting the gimbal bearing, bellows, etc.
Then, finally, when you get done with your drive maintenance, prior to filling with oil, you can (and very much "should") do a pressure test of the assembled drive to check for seal leaks.

Now you are at the point where you really need to pull the whole drive, drain the oil, and do the pressure test (using a soapy/water spray bottle to spray over the seals) and see where your problem lies.

You might even want to test just the lower half by itself before re-mating the drive halves together (will require you to insert a plug into the oil passage port.... I use a small tapered rubber plug for this.), since it sounds like your problem may (or may not) be present in the lower half.

Best of luck, and keep us posted!

 

[idflyfisher]

Re: Gear oil leaking from water intake on Alpha one???

Thanks for the info. I plan on all seals over the winter, but being in Idaho I would like to use the boat and save all the bench time for winter. Can anyone tell me how the oil is getting into the water inlet area. I have pressure tested the lower unit, and it holds pressure. if the previous O ring was bad, is there a way for the oil to get into that area??? The oil never made it to the upper vent hole, as it was leaking out of the weep hole on the starbord side, I suppose it could have drained into the inlet holes and I did not notice till I was trying to reinstall the lower unit after putting the new o ring on. I had no oil leaks issues when I tested it and found the water was not making it to the engine. Seems odd that I would have an all the sudden massive leaks in the lower unit, unless the misaligned water tube could cause such a problem. That said, I think oil would have shown up earlier, or water in the gear oil when I drained it. I had neither.

 

[Bt Doctur]

Re: Gear oil leaking from water intake on Alpha one???

you dis-assembled the upper to replace the 2 seals?? After you put the pump together you install the guide tube in the pump body, then put the upper unit on.

 

[ktbarrentine]

Re: Gear oil leaking from water intake on Alpha one???

I dropped the lower unit on my 4.3l mercruiser alpha gen+. and changed the impeller and the upper seals.

Hmmm...missed this particualr item the first time I read the post. If you only dropped the lower.....how could you replace the upper seals? (most of us would tend to think the upper seals you are referring to are the ones in the upper half of the drive that seal the vertical shaft). And if you actually replaced these two seals (which now sound like they could be suspect), it involved way more upper drive disassembly then was referred to here in this post. Guess we need more substantial details. The drive cant be having as big of an oil leak as you described if it actually passed a pressure test (either testing the lower half by itself, or testing the whole drive reassembled). Can you describe your pressure test procedure...It may help us understand the problem.

 

[idflyfisher]

Re: Gear oil leaking from water intake on Alpha one???

Sorry guys....its the whole noob thing. I guess the upper seals I am describing wrong. I only dropped the lower unit and did not mess with the upper at all. The guys at the boat shop believed that my losing oil was due to bad seals just below the pump. There are two seals in a convex carrier that I replaced. I could clearly see one of the old seals was folded, and believe this is where I was losing gear oil and was what the boat shop guys thought was the problem. I have the lower unit on the bench, and have corked the tube that goes to the upper unit and have a pump attached to the fill hole on the bottom of the unit. Holding at 10lbs for several hours now. Here is a theory, probably wishful thinking, but I am having a hard time believing something has gone majorly wrong. I pumped the gear oil into the reassembled stern-drive and it started leaking out of the weep hole because the o ring was bad. Over the course of 24+ hours (some at 100 degrees) some of the remaining oil soaked thru the water pump gasket and down into the water intake? As I said I am skeptical of my wishful theory, but no oil leaks when I tested with the misaligned water tube?

 

[Bt Doctur]

Re: Gear oil leaking from water intake on Alpha one???

We dont usually replace just the seals, we put a whole new base on.You say it did pass the pressure test though.The lower is empty during this test,correct. Try pressure testing the upper the same way and let us know the results.

 

[idflyfisher]

Re: Gear oil leaking from water intake on Alpha one???

I did pass the pressure test with the lower unit empty. I went out and put the lower unit on and attempted a pressure test on whole unit. I can get no pressure and can hear air thru the prop with every pump. I still think the tube from the lower to the upper is not sealing and that is what I am hearing. The small gasket on the lower unit seems insufficient. Is there supposed to be nothing in the upper section to help make the seal, just a gasket on the lower half?

 

[ktbarrentine]

Re: Gear oil leaking from water intake on Alpha one???

Try pressure testing the upper the same way and let us know the results.

It's a genII so he cant test the upper by itself without using a dummy vertical shaft. Only other alternative is to do what he did and reassemble and test the whole thing. I take it you still havent taken the upper off of the boat??????? The air you hear coming from the prop is air leaking by the tow upper seals that are supposed to seal the vertical shaft from the lower unit to the upper unit (my theory based on symptoms). That is why when you fill the drive, the oil never makes it to the upper vent because it is leaking by those seals in the upper.

I will repeat...You need to take the drive off of the boat and do a full 15 PSIG pressure test with the ability to actually see into the exhaust plenum and do a soapy water bubble check of those two vertical shaft seals (you will also be able to see the water pump tube and see if it is properly engaged in the upper). Taking the drive off the boat takes all of ten minutes and will give you a wealth of information. By the sounds of things, you wont eve need to use the soapy water to see/hear where your problem is.

Pictures of what you are looking at and talking about will help immensly, too.

Keep us posted!

 

[Bt Doctur]

Re: Gear oil leaking from water intake on Alpha one???

not stated that its a GEN II. so I`m going with a normal Alpha 1
Just the quad seal that goes over that hole in the lower.nothing between the halves.
You have stated the lower passes the press test, test the upper the same way to see if you can get some pressure. holding a finger over the hole should work for a quick test.

 

[ktbarrentine]

Re: Gear oil leaking from water intake on Alpha one???

I looked at his previous threads/posts.... This is a '97 4.3 w/ Alpha 1 gen+. I still think it is time he pulled the upper off the boat and did his diagnostics on the bench.

 

[Bt Doctur]

Re: Gear oil leaking from water intake on Alpha one???

The guys at the boat shop believed that my losing oil was due to bad seals just below the pump

sure sounds like the carrier below the impeller but he dosent state what drive.
never checked for other posts. If a GEN II he cant test just the upper.And to replace those the upper has to come apart.Could install in on a bench to check and see any oil running down the vert shaft.

 

[ktbarrentine]

Re: Gear oil leaking from water intake on Alpha one???

There are two seals in a convex carrier that I replaced. I could clearly see one of the old seals was folded, and believe this is where I was losing gear oil and was what the boat shop guys thought was the problem.

A gen II with multiple problems!!!!

 

[Bt Doctur]

Re: Gear oil leaking from water intake on Alpha one???

is it # 19 Sterndrive Exploded Views F : MerCstuff.Com

 

[greekfreek]

Re: Gear oil leaking from water intake on Alpha one???

Really it is SO much easier to take the whole drive off, set it on a home made stand and assemble it that way...seeing that the water tube is aligned... and pressure testing it. I've been there thinking I could assemble with out taking the upper off...

 

[idflyfisher]

Re: Gear oil leaking from water intake on Alpha one???

Sounds like it is time to take the whole thing off. Very FRUSTRATED. I believe it is a gen II. Looks exactly like the diagram. I am going back down to the boat shop to speak with those guys. I will also see if I get pressure on upper half while on and keep you all posted. Thanks for the info/help

 

[idflyfisher]

Re: Gear oil leaking from water intake on Alpha one???

Tried pressure test with finger over that connects lower to upper. No pressure, can hear and feel air moving where driveshaft seats into upper. I still am planning on going to the shop to talk with the pros.

 

[ktbarrentine]

Re: Gear oil leaking from water intake on Alpha one???

Tried pressure test with finger over that connects lower to upper. No pressure, can hear and feel air moving where driveshaft seats into upper. I still am planning on going to the shop to talk with the pros.

Tried to explain that you cant test the upper by itself on a genII... you need to either use a dummy shaft inserted into the two shaft seals, or reassemble the drive and test the whole thing.

Have you removed the upper from the boat yet??

 

[ktbarrentine]

Re: Gear oil leaking from water intake on Alpha one???

It's a genII so he cant test the upper by itself without using a dummy vertical shaft. Only other alternative is to do what he did and reassemble and test the whole thing. I take it you still havent taken the upper off of the boat??????? The air you hear coming from the prop is air leaking by the tow upper seals that are supposed to seal the vertical shaft from the lower unit to the upper unit (my theory based on symptoms). That is why when you fill the drive, the oil never makes it to the upper vent because it is leaking by those seals in the upper.

I will repeat...You need to take the drive off of the boat and do a full 15 PSIG pressure test with the ability to actually see into the exhaust plenum and do a soapy water bubble check of those two vertical shaft seals (you will also be able to see the water pump tube and see if it is properly engaged in the upper). Taking the drive off the boat takes all of ten minutes and will give you a wealth of information. By the sounds of things, you wont eve need to use the soapy water to see/hear where your problem is.

Pictures of what you are looking at and talking about will help immensly, too.

Keep us posted!

...

 

[idflyfisher]

Re: Gear oil leaking from water intake on Alpha one???

Went and spoke with the guys at the boat shop at length. Their best guess is that I displaced the oil seal in the upper while inserting the shaft. That makes sense to me as I had a hell of a time getting it to seat properly. They say it is possible to get up there with a homemade tool and try and get it reset. That may work if......I did not damage the seal. I have opted to take it down to them and have them do the job. Sounds like special tools are need to replace the seal if it is damaged.
Thanks to all that responded to my questions, really do appreciate all the info and help provided.