aq125 fresh water impeller/bearing seal leaking.-gctid397875

[Guest]

Hello, Great forum and I have learned some already. I am having cooling issues, boat is 1982 capri 1950 with VP 270 outdrive and Aq 125. after 1hr of run time i checked the engine compartment for any leaks or problems and saw some slow leaks......one was a dribble others were drips/1-2 per second. engine temp was ok at around 185-190. Temps started to rise while we were running 3500 to 4000 rpms. Headed for the dock at 3000 rpm and found the temps rising so Idled down and limped in.

Trouble shooting system today I found the bearing/seal on the back of the freshwater was rusted and leaking. any advice on where to get parts and process for replacement would be great. Impeller is has 4 hrs on it from last season.

did the failure of the bearing cause a lack of circulation pressure? (increasing the temps as the bearing got worse?) I did not find any anti-freeze in the bilge and the level was ok.

Thanks again

Rick

Great Falls MT.

[Guest]

This is what I do. I go to the site in the link, find my engine, get the part number. Then I punch the part number into Google and find places with good prices that have it in stock.

http://www.marinepartseurope.com/en/volvo-penta-cat-7744650.aspx

[Guest]

Hey, that was great........now i have the part number and will run over to the local shop and check for it, hope they have it. otherwise its online order time. I was thinking of ordering the brass bushing but dont think I can remove them with the hand tools I have. anyone wanna give me some hints/advice on R-R?

[Guest]

what is up with the gasket? white foam ? tried to put the cover on and the gasket just squeezed out and broke. anyone know of a real gasket I can buy! dealer said foam is all he can get. has anyone made one the old fashioned way? what did you use? where did you get it.

Thanks

[2850Bounty]

This is your "sea water" pump.... not a fresh water pump!

The white cover plate gaskets work perfectly when applied correctly. Take another stab at it...., you'll get it.

Here's something else that you need to routinely replace on your stern drive.

The water neck fitting and special beaded gasket.



These become corroded and will allow the hose connection to loose it's seal.

When up on step, this part raises out of the water.

One tiny suction breach here, and you'll loose all sea water pump ability.

If you are due for drive shaft bellows replacement, now is the time to do both while the transmission is removed.

While there....., I'd suggest that you pull your PDS and replace the single bearing.

(see Ryan's thread for this in the BOC Vault)

.

[Guest]

Thanks for the reply....I guess I was a bit frustrated when I posted fresh water pump. could you give me a idea of the correct way to install this gasket? I feel like as soon as i tightend the bolts down it just squeezed out the gasket. I put silicone gasket goop on it....is that a no no?

anyway.....any help or hints would be great.

Thanks

[2850Bounty]

Yes, but please don't discount the importance of replacing this water neck fitting.

Nine times out of ten, this part needs to be replaced..... and in particular when owners are not aware of it's importance, or that it is out of the water once up on step.

As for the white gasket, it's normal to see it squeeze out equally around the perimeter.

If you used a silicone product on it, it may have lubricated it, and may have caused it to squeeze out even more so.

Install this gasket dry!

.

[Guest]

And don't overtighten. When you see it start to squeeze out it is tight enough. It is a fairly thick gasket and seals really well. And yes, the silicone probably made it extra slippery.

[Guest]

I had a similar problem with my first boat, and it turned out the manifold was partialy plugged with rust and was overpressuring the cooling system. When I replaced the impeller with a fresh one it built so much pressure it pushed the seal out the back of the bronze housing.

The manifold was toast but I had one in decent shape on a parts engine that I had boiled out and it worked fine.

It could be that your seawater pump has a million hours on it and may just need a new bushing and seal, but typically leaks are a sign of other problems.

Remove the rubber exhaust connector and see how the water ports look at the end of the manifold, there should be 3ea about 1" long and 5/16" wide slots which spray water into the exhaust downpipe at 12,4, and 8-o-clock, and a smaller one at the bottom so the manifold drains. If these are all caked with rust and plugged it's time for a new manifold.

The water neck is also a common problem, and as you get on plane it comes out of the water and sucks air in with the cooling water, then you slowly overheat. Because the transmission has to come off to access it, it's one thing leading to another and you'll want to look at bellows, primary drive shaft bearing, and maybe u-joint crosses and transmission seal if the bellows are breached. Avoiding any of these issues will lead to more expensive parts failing and possibly more overheating so if you wish to keep the boat the time is now to go thru it.

[Guest]

Thanks guys, this is exactly what i need to know.......I will get to work. R

[Guest]

rickg wrote:
Thanks guys, this is exactly what i need to know.......I will get to work. R

Go to our vault and read up....download the manual for your motor as well.

[Guest]

Thanks guys...update is took it to the lake after running it in the drive way. I used the water hose and plumbed into the flex hose at the aft part of the engine. saw a little leak in the seal at the intake line for the sea water pump.....but it stopped after a sec or 2.....so I figured no problem. that may be a mistake.....took it to the lake for a short test and it lost prime and really got hot. Got it home and started looking at the hose and connection from the transom to the lower unit. I removed the hose and was shocked to see the corrosion on the hose connector (the one you guys show in the previous post) It needs to be replaced. I also found a dry rot crack on the bellows that has the u joints in it, lucky for me it shows now damage and only slight surface rust. Still lots of grease on the splines and u joints...no loose u joints. Now upper trans is off and bellows is out. I was going to order the bellows,hose, hose connection w gasket and reassemble the unit. I am wondering if I should do anything else....any one want to jump in here and make a suggestion? Nows the time right? bounty said ... I'd suggest that you pull your PDS and replace the single bearing. I will go see i f i can find out what this is......

Thanks

Rick

[2850Bounty]

rickg wrote:
Thanks guys...update is took it to the lake after running it in the drive way.

1.... I used the water hose and plumbed into the flex hose at the aft part of the engine. saw a little leak in the seal at the intake line for the sea water pump.....but it stopped after a sec or 2.....so I figured no problem. that may be a mistake.....took it to the lake for a short test and it lost prime and really got hot.

2..... Got it home and started looking at the hose and connection from the transom to the lower unit. I removed the hose and was shocked to see the corrosion on the hose connector (the one you guys show in the previous post) It needs to be replaced.

3.... I also found a dry rot crack on the bellows that has the u joints in it, lucky for me it shows now damage and only slight surface rust. Still lots of grease on the splines and u joints...no loose u joints.

Now upper trans is off and bellows is out. I was going to order the bellows,hose, hose connection w gasket and reassemble the unit.

4.... I am wondering if I should do anything else.... any one want to jump in here and make a suggestion?

5.... Nows the time right?

6.... bounty said ... I'd suggest that you pull your PDS and replace the single bearing. I will go see i f i can find out what this is......

Rick, both Ryan and myself routinely suggest inspecting and/or replacing these items from our own past experience.

Neither of us want any members to have trouble related to a failure with any of these critical components. Key words; critical components.

1.... IMO, circumventing the OEM system in order to perform a test, defers real world trouble-shooting and maintenance. I never suggest doing this. Do what is protocol, you'll find the problem area, and you will not have any issues.

2..... Not beating you up here.... but again, this is why we make these suggestions.

The water neck fitting should be considered a "wear item" that requires routine replacement.

This part comes up and out of the water when the hull is at planing attitude.... and that's likely why you over-heated.

3.... See above.

4.... PDS bearing, perhaps bearing cross replacement, complete drive re-seal, and perhaps upper pivot tube bushing.

If the upper pivot tube bushing allows the tube excessive play, the water neck beaded gasket will hold for a short duration only.

5.... Absolutely!

6.... Ryan should have you covered in his BOC Vault thread.

OHC 4 cylinder engine single bearing PDS will come out AFT without pulling the engine.

Early GM V-8 double bearing PDS requires engine removal.

Later GM V-8 single bearing PDS is similar to the 4 cylinder engine PDS.

.

[Guest]

The PDS bearing and seal is not hard to do, again, covered in the vault(link below).

I drive a pair of drywall screws thru the rear PDS seal and then grab them with pliers to remove.

After that you need a long set of snap ring pliers or grind a set of long nose pliers to suit. It helps to buy a replacement snap ring and then fit your customized pliers into it so you don't have to fight getting the ones out of the boat as much.

Snap ring behind the seal comes out, then another further in.

Then I have a (banjo's start strumming) big pair of vice grips that I grab the end of the PDS shaft with, run a cable thru them, and wrap the cable around something heavy to use like a slide hammer to eject the shaft.

Beat the old bearing off the shaft, clean it up and put it in the freezer. Wrap the new bearing in foil and warm it in the toaster oven, then use a brass bar or proper sized piece of pipe to tap on the INNER race to install the new bearing to the PDS shaft.

[Guest]

Where would you suggest getting the correct oil for the lower unit? also I need to get some of the correct gasket sealant. (IAW the aq270 lower unit manual permatex 679 is what they use for the mating surface of the upper case to the middle case.) I was wondering what I need to use for the 'cooling neck gasket'.

(I have some 'permatex #3 D aviation form a gasket, sealant liquid, pn; 80017.) ....Thanks for the help, I think I have a handle on how to do it now. Parts should be here friday, just need to figure out were to get the oil and gasket sealant.