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Delete the Generator Sea Water Pump Impeller?

Discussion in 'Generators' started by Thisisit, Jun 8, 2025.

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  1. Thisisit, Jun 8, 2025
    #1
    Thisisit

    Thisisit Member

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    I can't find the original thread about this issue, so I will re submit my question.

    Has anyone removed the impeller from their genny pump housing and replaced it with an electric pump setup?

    My Westerbeke 8.0 BTD is mounted in such a way that the seawater pump is on the back side.

    To change it out, I need to disconnect a whack of wiring and hoses, un-bolt the unit from the mounts and spin it at least 45 degrees. Then, I have to work left-handed (not that there's anything wrong with that) and with very little room and leverage.

    I understand that some have removed the Impeller, installed an AC pump and wired it into the AC output of the genny to provide the genny an uninterrupted supply of seawater.

    Has anyone had experience with this setup?
  2. Thisisit, Jun 8, 2025
    #2
    Thisisit

    Thisisit Member

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  3. Capt Ralph, Jun 9, 2025
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    Capt Ralph

    Capt Ralph Senior Member

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    Well, It been six years already. How many impellers have been replaced since this first job?

    I do have another thought to ad not considered in the original thread; GPH..
    Not enough may not cool the engine and exhaust well.
    To much may cause exhaust restrictions or flood the engine with water.

    Try to find or calculate the gen-sets raw water flow, GPH or GPM and match a 230Vac pump to that.
  4. Pascal, Jun 9, 2025
    #4
    Pascal

    Pascal Senior Member

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    That’s going to be tricky part: sizing the pump.

    march pumps are probably your best option if you go that route, they come in a variety of flow rating and are easy to service. Stay away from Cal pumps

    best advice for those reading this thread? Don’t buy a boat with lousy service access. A raw pump should be easy to access not buried behind the gen.
  5. Capt Ralph, Jun 9, 2025
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    Yep..
  6. jhall767, Jun 9, 2025
    #6
    jhall767

    jhall767 Senior Member

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    I would wire it to a relay with a hobbs oil pressure switch. This will prevent it from running when the engine is not running. Otherwise you could flood the cylinders.
  7. MBevins, Jun 9, 2025
    #7
    MBevins

    MBevins Senior Member

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    As well as the reverse, you should monitor the electric pumps outflow
  8. Thisisit, Jun 21, 2025 at 11:44 PM
    #8
    Thisisit

    Thisisit Member

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    Jhall767: The start up and shut down of the pump is the easy part.

    Ralph: There does not seem to be open source information on the water flow rate. I can say that from my observations, even a relatively small pump, say 500 GPH is more than enough. This does present a back flow problem as 500 is too much. And BTW, 2 impellers since then (routine maintenance).

    Gonna pour a cocktail and let Occam's Razor rule this process. It seems the solution I currently have is the right one...for now.
  9. Capt Ralph, Jun 22, 2025 at 12:35 AM
    #9
    Capt Ralph

    Capt Ralph Senior Member

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    Here in the swamps, we call it KISS.
  10. Capt Ralph, Jun 22, 2025 at 11:40 AM
    #10
    Capt Ralph

    Capt Ralph Senior Member

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    I woke up this morning (late) with another thought.

    Many (many) years ago I tried the early Globe impellers.
    I did not like them, impeller blades were to soft and they sailed in the pump not pumping the same potential as the original rubber.

    A couple of years ago we tried them again in a customers troubled NL-12.
    Wow, what a difference than before. They are a lil stiffer, pump all the water and are racking up hours, hours, hours when the rubber impeller in the NL-12 would have long failed.
    Last year I installed one in our lil gen-set.
    Including a sea-weed blockage/ over heat/ shut down, a few 100 hours later it is still pumping great.
    Sadly, Globe impellers are not available for our big gen-set and I fear with half the hours, it may need servicing.

    I bring all of this up not to sell Globe impellers but to offer an idea that may help those hard to reach pump installations, not require servicing so often.

    I used to bad mouth them, but these days, I'm impressed.

    It's still KISS, just maybe reduced servicing.
  11. Pascal, Jun 22, 2025 at 2:31 PM
    #11
    Pascal

    Pascal Senior Member

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    Pull the water hose from the water lift muffler, seal the hole in the muffler, put the water hose in a 5 gallon bucket, start the gen, start the timer. That will give you an idea of the flow

    wait let me guess, you can’t reach the muffler ? :)