Fresh water pump leaking

[MarkVon]

After noticing my coolant was low, I topped it up and then started the engine and looked at the fresh water pump and noticed it was leaking. Here’s a video of the leak:

https://youtu.be/BFfKTZYoUpg

I replaced the impeller and rubber ring a few months ago. Do you have suggestions for tackling this problem? Thx!

[MarkVon]

I just clamped off the two hoses connected to the pump and removed the cover. Cover seems fine. Rubber ring seems fine. There isn’t a gasket though...

I put a small amount of permatex gasket maker around inside edge of the plate and put it back on. I removed the clamps and it’s still dripping..

Here’s a video from underneath showing the leak and below is a wider picture:

https://youtu.be/cT2S3PpGIs8 (the sound is the bilge blower, not the engine)

The drip seems to be forming from further back on the pump, rather then the pump plate. Any thought/tips appreciated!

[edwardc]

It’s probably leaking from the “weep hole” on the underside, indicating that one of the seals is shot. A rebuild kit can fix that.

[MarkVon]

Thx Edward! Here’s a video from the reverse position, looking from the back of the pump:

https://youtu.be/tJe3F4vaC7I

Leak definitely seems to be coming from the ‘weeping hole’, rather then the cover. Given, I just changed the expeller and rubber ring, what parts of the rebuild kit do I really need?

[Peter]

Mark,

There are two rubber seals in the pump housing that are supposed to seal

1) the coolant side of the pump, and
2) the accessory drive side of the pump

You may want to pull the pump shaft and inspect it for wear - if it is badly worn replacing the seals will be for nought. You can get a new shaft but you may also wish to consider the MMI pump.

HTH,

Peter

[edwardc]

Thx Edward! Here’s a video from the reverse position, looking from the back of the pump:

https://youtu.be/tJe3F4vaC7I

Leak definitely seems to be coming from the ‘weeping hole’, rather then the cover. Given, I just changed the expeller and rubber ring, what parts of the rebuild kit do I really need?

Shaft, seals, and bearings. In my experience, when the seal goes, the shaft gets worn, and a new seal won’t seal to it. Similarly, once water has gotten to the bearings, they will degrade and fail over time.

[capnward]

Check your pump for leaks

Yup, been there, done that. The pump leaked so much past both seals that despite the weep hole, water got into the accessory drive and into the crankcase. The back of the pump at the accessory drive looked like a vanilla shake had been poured into it. Oil on the dipstick was grey. I had neglected to notice the leaking pump, until the engine overheated because the pump was putting water into the bilge and crankcase as much as into the block. I had a Moyer rebuild kit ready to go, and the problem was fixed in a few hours. Shaft, seals and bearings were all replaced. One bearing wouldn't even turn. Then 3 oil changes were needed.
So deal with your leaking pump right away, and maybe you will only have to replace seals, instead of the shaft and bearings also. But it's likely you will need all new parts, as Edward says. Carry a complete rebuild kit. Best to have a spare pump as well. Rebuilding a water pump is not the kind of job you want to do while sailing.

[W2ET]

Hi, Mark:

Suggest you view the flange pump rebuild video to get an idea of what's what inside the pump.

Bill

[Al Schober]

Those old Oberdorfer pumps do wear out. I struggled with mine for years. New seal, new shaft, different seals.
When I changed to glycol cooling, I wasn't leaking sea water any more. I was leaking glycol coolant. It was like having an open artery pumping blood into the bilge!
A new pump from our host (ball bearings, face seal) fixed the issue.

[JOHN COOKSON]

Those old Oberdorfer pumps do wear out. I struggled with mine for years. New seal, new shaft, different seals.
A new pump from our host (ball bearings, face seal) fixed the issue.

My experience also.

I want to add that when I went to a Moyer pump my running temp at cruise RPMs dropped 20 degrees. (RWC engine) The Moyer pump is a much better pump.

ex TRUE GRIT

[MarkVon]

Thanks everyone! I’ve ordered a pump rebuild kit from MMI.

I spoke with Ken at MMI and he said I could use the engine for getting in and out of our mooring bay for day sails, but to keep a close eye on it and no big trips until I’ve rebuilt it.

[wakemutant]

Replacing a water pump requires a fair amount of technical expertise. Are you planning on installing a new water pump? Changing a water-pump impeller is normally a straightforward job that every boater should be able to tackle. Impeller pumps are far more common than you might imagine and are used for everything aboard from bilge and shower pumps to freshwater and seawater washdowns fishing in uae. Generally, they can be relied upon to work without incident for many months or even years, but that doesn't mean they're maintenance-free.

[JOHN COOKSON]

Replacing a water pump requires a fair amount of technical expertise.

NOT REALLY. IT DEPENDS ON HOW MANY TIMES YOU'VE DONE IT.
FOR NEW BEES HERE'S A BRIEF GUIDE.

Removal:
Pull the impeller and shaft out of the pump if possible. Remove the upper easy bolt. With any luck the pump will rotate on the lower bolt making access easier.
If you can't get the shaft out of the pump before removing the pump skip this step.

Install:
Thread a stud finger tight into the lower hole. If you don't have a stud buy a bolt and cut the head off. Slide the pump on the stud and line up to the upper hole. If the shaft is in the pump at this stage rotate the shaft until the shaft drops into the keyway on the engine. This isn't as hard as it sounds. (usually)
If the shaft and impeller are removed you can twist the shaft and impeller in after the pump is mounted on the engine.
Once everything is lined up instal the upper bolt and tighten firmly. This will hold the pump in place while you twist the stud out and install the lower bolt. Loosen the upper bolt then torque both bolts evenly to sort of loose snug. Turn the engine a few times with the starter. This will line everything up properly. Then finish torquing both bolts evenly.
Hint: Cleanup all the threads. Depending on your access a lot of this will be done by feel. Clean threads will give you a sensitive feel and prevent cross threading.

ex TRUE GRIT

[MarkVon]

Thanks for the support everyone!

The rebuild kit from Moyer Marine arrived yesterday and I installed it last night. Pretty straight forward (apart from awkward access) thanks to MMI's instructional video:

https://youtu.be/lKKJc02PAQE

I really appreciate this community and the excellent service from MMI.

Now off for a five-day winter sailing trip tomorrow!


m

[joe_db]

Replacing a water pump requires a fair amount of technical expertise. Are you planning on installing a new water pump? Changing a water-pump impeller is normally a straightforward job that every boater should be able to tackle. Impeller pumps are far more common than you might imagine and are used for everything aboard from bilge and shower pumps to freshwater and seawater washdowns. Generally, they can be relied upon to work without incident for many months or even years, but that doesn't mean they're maintenance-free.

Not really - it is two bolts. What it requires is being triple-jointed and tolerant of sharp objects digging into various parts of your body.