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Crusader Impellers

Discussion in 'Carver Yacht' started by seldomdry, Oct 24, 2012.

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  1. seldomdry, Oct 24, 2012
    #1
    seldomdry

    seldomdry Member

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    Freshwater boat. Whats the life expectency of the raw water impellors?
  2. Capt Ralph, Oct 24, 2012
    #2
    Capt Ralph

    Capt Ralph Senior Member

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    I would not push past 1 year fresh or salt.
    That said, I have seen fresh water impellers last longer. I would only assume less hours. I have also witnessed on small rigs in lakes around Atlanta, impellers lost within a year due silt/sediment in the shallows.
    It's cheap insurance, replace them. AND,,, every time you think you may have run shallow and picked up extra sediment.
    Would you risk overheating a big dolor motor on a cheap part replacement? Think about it every time you change the oil & filters.
  3. RB480, Oct 24, 2012
    #3
    RB480

    RB480 Senior Member

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    I do mine on lake Michigan every 3 years now. It's not uncommon for them to last a long time... Like 14 years on my personal boat. Cheap insurance to replace every once in a while. I always keep spares on board
  4. RB480, Oct 24, 2012
    #4
    RB480

    RB480 Senior Member

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    I do mine on lake Michigan every 3 years now. It's not uncommon for them to last a long time... Like 14 years on my personal boat. Cheap insurance to replace every once in a while. I always keep spares on board as well.
  5. Capt Ralph, Oct 24, 2012
    #5
    Capt Ralph

    Capt Ralph Senior Member

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    14 years?

    Yes , cheap insurance. But why rely on spares? Replacing an old impeller on a hot motor, on a hot day, with family and friends lurking over your back (un armed?) when you were just down in the bilge changing the oil last week.

    Always keep spares, Always keep a good impeller in da pump first. When in doubt, replace it.
  6. Kafue, Oct 24, 2012
    #6
    Kafue

    Kafue Senior Member

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    I had a question regarding impellers, but first, have to ask, what do you mean "un-armed!"
    Re impellers, I checked the Port engine one while we had the GB off and it seemed fine. Both engines were done (DD12V71N's) 250hrs ago so I thought to leave them another year or so, also, surely I am not risking an overheat as an "overheat" alarm would go off before that, right?
    Now, as an ex-Rhodesian, please fill me in on the "un-armed" bit and please don't tell me you guys live like that:)
  7. Capt J, Oct 24, 2012
    #7
    Capt J

    Capt J Senior Member

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    It's recommended to replace them 2 years or 250 hours, I wouldn't go any longer on the smaller gas engine impellors. Generator impellors I do once a year.

    On the larger Cats and MANs with the really large impellors they recommend inspection at 250hrs, replace 500hours.....but the impellor manufacturer such as Jabsco or Johnson recommend 250 hrs and I'd recommend that as well.
  8. Pascal, Oct 24, 2012
    #8
    Pascal

    Pascal Senior Member

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    I find that in boats used year round impellers last a long time whether diesel, gas or gensets (3 to 6 years and up to 2000 hours)

    On boats that are hauled out for winter or that sit a lot impellers take a set and may not last as long

    It is rare for impellers to disintegrate without warning. When you can observe exhaust flow, a worn impeller will be noticeable by reduced flow. On engines with accurate gear temp gauge, raw water flow issues will often start with the gear running a little warmer than Normal
  9. RT46, Oct 25, 2012
    #9
    RT46

    RT46 Senior Member

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    once a year to be safe.

    you might get away with every other year, or more, but not worth the cost of cooking your engine.

    Pascal is right on the money, boats in constant use tend to have the impllers last longer because they dont get "set" during lay up.
    You could remove the impeller during the winter to extend the life, but once it is out you might as well replace it.
  10. Capt Ralph, Oct 25, 2012
    #10
    Capt Ralph

    Capt Ralph Senior Member

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    Hot day, boat not moving, family and friends get upset in a hurry. Tempers get short quickly and usually the wife starts her gripping first. All this time your head is in the bilge with your back toward them.
    un-armed is my s/a comment that reminds the captain not to allow weapons on board.
    With a imaginative seen like that to remind you, Keep a smile on all and replace the impeller before it fails.
  11. Maxwell, Oct 25, 2012
    #11
    Maxwell

    Maxwell Senior Member

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    I do ours annually on the mains (VP Diesel) and 2x per season on the genset (onan). We put approximately 200 hrs on the mains annually and maybe 150 on the genset. I have had 2 genset impellers fail and finally decided that it was a lot easier to change out an intact impeller rather than try and fish out the parts of a failed one.

    max
  12. Pascal, Oct 25, 2012
    #12
    Pascal

    Pascal Senior Member

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    Twice In a season is abnormal. There has to be a reason for such early failure.

    I had two impellers fail after a few months and 150 hrs on a pair of cats 3412 while the previous set had lasted 1500hrs and 4 years. Turned out to be debris on the inlet side of the fuel cooler which is on the suction side of the raw water pump. There was also a very small air leak on the suction side (hose) which was invisible but could be heard on shut down
  13. Maxwell, Oct 25, 2012
    #13
    Maxwell

    Maxwell Senior Member

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    I agree... The first time (last season) I found I had ingested some weeds etc but the second time it failed (this season) the strainer etc was clean. However it happened days after we were in a sandy shallow anchorage in Canada which leads me to believe we likely sucked up some sediment... This did make me a bit gun shy as to fish the little pieces out you have to remove the oil filter (lovely design).

    max