Johnson Waterpump Help

[Kenomac]

If it's not one thing, it's another. How do people who aren't handy handle these situations?

A week ago, our Westerbeke Generator Waterpump impeller exploded, so today we finally found a new one and tried to install it. It didn't go well, we noticed some corrosion around the base of the Johnson water pump where the drive shaft is exposed and I felt a little 1-2mm play in the driveshaft which didn't seem normal. The plan was to install the new impeller and see if there was a water leak coming from the base of the pump, which would probably indicate worn out bearings or a seal, but we couldn't get the new impeller to fit inside the drive shaft slot; the pin seemed a little too wide. The old impeller pin is noticeably smaller, but it looks as though the difference in size was due to corrosion. Both impellers, new and old are the model 810. OEM

Any mechanics whith suggestions? Should I just order a complete new pump at this point. Hopefully, you can see the corrosion in the pictures.

Thanks

Ken

[DougR]

The corrosion which you see on the pump body at the weep hole indicates water leakage past the pump water seal. This is understandable. With 2mm play in the shaft it will be about impossible for any seal to control leakage. The pump needs to be rebuilt with new bearings, oil seal, water seal and impeller. It might also need wear plate, cam (if replaceable), and cover plate.

Might be best to replace the pump and rebuild the old one at your leisure for a spare.

DougR

[Kenomac]

Originally Posted by DougR

The corrosion which you see on the pump body at the weep hole indicates water leakage past the pump water seal. This is understandable. With 2mm play in the shaft it will be about impossible for any seal to control leakage. The pump needs to be rebuilt with new bearings, oil seal, water seal and impeller. It might also need wear plate, cam (if replaceable), and cover plate.

Might be best to replace the pump and rebuild the old one at your leisure for a spare.

DougR

Thanks Doug.

Just as I suspected, been through this many times with automotive water pumps. Is this also the possible reason for the impeller to fail so quickly? I forgot to mention in my earlier post that I noticed a puddle of water, of significant quantity on the tray below the genset.

[DougR]

Don't know that 2mm play would cause the impeller to go prematurely, but it couldn't help things. What do you consider premature?

If you disassemble the pump you will have a clearer picture of the impeller pin and drive shaft slot, and be able to figure out why the pin wouldn't fit the slot. Maybe there is a little bit of a burr or distortion from wear....a couple of strokes with a fine file might solve that.

DougR