raw water pump 3GM30F

[BobH260]

I am on a cruise in Bahamas, I just discovered the shaft seal is leaking on the water pump">raw water pump, 500 hrs on engine. Can this seal be replaced in the field ? Is it an O-ring ? Will it cause the bushing to seize ? I am getting about 2 quarts of water under the engine with 8 hrs of hard running.

Bob

[jimbunyard]

Yes the seal can be field serviced, no it is not an oring, (there may be an oring as an integral part of the lip seal, typically raw water pumps have 2 roller bearings that are not affected by a water leak.


You can find a thread about this by Belizesailor by searching this topic here on CF:


Quick Raw Water Pump Sea Water Seal Replacement


I would only do this as a quick fix, may be just me, but I like to clean everything up and check the bearings, polish the shaft and change the oil seal and impeller all at one go.


Also be aware that if you change the spring in the seal with an o ring, the o ring typically has a shorter life than a spring and will cause the seal to leak as it hardens, the seal lip may still be fine...


One should keep a couple seals and an impeller for spares for just this occasion (and learn the way to change them). It's a good idea to change them every 3 years or so, to keep your spares fresh (they deteriorate with age).

[DotDun]

The seal that's leaking is a lip seal. You have to remove the impeller and you'll see the lip seal around the shaft at the housing. Some are successful in removing the lip seal without taking the shaft out, I like to remove the shaft and inspect the bearings on the other end. If you remove the shaft, be aware the nut on the other end is left-handed thread. Also, you'll need to press (or tap) the shaft out, I have a block of wood with a hole in it and tap with hammer/punch (same with bearings on/off the shaft).

You'll find an o-ring on the shaft in the 'vented' area that appears to serve no purpose. It is there as a 'slinger', it's suppose to 'sling' the water away when the seal leaks before it gets to the bearings. My guess with the amount of water you describe is leaking, your bearings are already corroded and need replaced also.

Yammar used 2 different model pumps on the 3GM30 depending on where the engine was manufactured/sold. The "YEU" model uses a cheaper pump (about 1/2 the cost), but it doesn't have a changeable cam/backing plate.

A parts list for the YEU model:

http://www.depcopump.com/datasheets/...0-24509-01.pdf

All the parts and new pumps are available at:

Depco Pump Company

Depco Pump Company Marine Catalog 111

Good Luck!

[jimbunyard]

Correction, the bearings are typically ball bearings.

[BobH260]

Thanks for all the detailed information, that is just what I needed to know.
Bob