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  1. #1
    mikesxpress
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    Bilge pump education.

    Still pretty dead in here. How about some practical FYI?

    Just went thru this with a guy on his winter to do list items as he was replacing pumps. May help someone else?

    Engineering notes:
    1. A 750 GPH pump in the bilge that has to lift the water (in a 7/8" ID hose) more than 12" loses 15% of it's rated capacity. 14-18" lift looses 25%. Any bends (that don't crease the hose) will reduce the flow another 10%+.
    2. Adding a check valve reduces the GPH by 13%.
    3. Plumbing two 750 GPH pumps into one 3/4" discharge hose is not recommended. Even with a Y fitting and not accounting for the lift reduction the maximum a 3/4" hose can attain is 1100 GPH. Enter in the two pumps discharge flow meeting at the Y can cause cavitation of both pumps. *Yep. A few older hulls came like this.

    While most OEM'S install 750 GPH bilge/livewell pumps, the average lift from the bilge to the discharge degrades them to 562 GPH.
    Adequate?
    Maybe, but maybe not?

    Suggested alterations:
    Upgrade fuses to 6 amps for both the automatic bilge and manual bilge.
    Install Johnson Controls 1000 GPH automatic (sensor controlled not float switch) bilge pump and Johnson Controls 1000 GPH manual bilge pump on separate 3/4" hoses. No check valves and large radius turns in the hose routing. With the average degradation of lift these pumps they will give you the 750 GPH you thought you had previously. Spearing a wave or a rogue back deck wash can fill a boat in a hurry. You want maximum pumping happening then. Best to have the max pumps in place and the upgrade cost is minimal over the 750's.

    *These 1000 GPH pumps will draw more amps. On/off use such as rain water pump out is not an issue but if you take a huge volume requiring extensive pump time keep the engine running.
    Side note: Any other 12VDC pumps rated over 1100 GPH will require 1 1/8" inside diameter hose.
    Last edited by mikesxpress; 01-06-2019 at 06:13 AM.

  2. Member
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    #2
    Good info. Thanks
    William "Bill" Kyte
    Waldorf, MD
    2018 Shenadoah Kerr lake BFL Co-angler Champion

    2020 Ranger 520L Evinrude G2 250HO

  3. Member
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    #3
    Intersting topic....

    I am looking at my live well pumps....Amp draw wise. Have an issue when running live well pumps my battery struggles. No livewell pumps no issue. I am running a group 31 X2.

    2023 Phoenix 920 Elite
    2023 Mercury Pro XS 4S

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    #4
    Thanks for sharing this info...
    1999 Stratos 273 Vindicator 2013 Yamaha 150hp HPDI Vmax

  5. mikesxpress
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    #5
    Quote Originally Posted by Beallright View Post
    Intersting topic....

    I am looking at my live well pumps....Amp draw wise. Have an issue when running live well pumps my battery struggles. No livewell pumps no issue. I am running a group 31 X2.
    You have one of the two best batteries available.
    Need to have the boat in the water with pressure on the pumps and connect an amp meter. Turn each pump on one at a time and record the amp draw. Have all your other gear including electronics turned off. Then leave the pumps off and turn on your electronics one at a time. The objective is to determine each items amp draw.

  6. Member
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    #6
    Quote Originally Posted by mikesxpress View Post
    You have one of the two best batteries available.
    Need to have the boat in the water with pressure on the pumps and connect an amp meter. Turn each pump on one at a time and record the amp draw. Have all your other gear including electronics turned off. Then leave the pumps off and turn on your electronics one at a time. The objective is to determine each items amp draw.
    In your opinion would filling the wells at home and putting them in recir provide the same load as on the water.. Or do you think the water being brought in more an amp draw?

    2023 Phoenix 920 Elite
    2023 Mercury Pro XS 4S

  7. mikesxpress
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    #7
    Have to load the impellers from the outside just like you would use them. I was on the river today for 4 hours. Muddy and a few floaters but not bad.

  8. Member
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    Shepherdstown, WV
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    #8
    Since I fish the type of water where hitting rocks is inevitable, even with a 1/4" plate hull, I'm running two 1200 gph pumps with 1 1/8" hoses and fittings.
    2022 Hog Island Skiff
    Johnson 70/40 jet

    Bouncin' off rocks, and catching the smallies.

    Potomac River Smallmouth Guide

    Owner of Potomac Custom Tackle

  9. mikesxpress
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    #9
    Josh your jet boat running the rivers up there are for sure going to need way more pumping than us prop driven guys. Were not running thru rocks intentionally.

  10. Member mikesjet's Avatar
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    #10
    Mike,

    Will the 1000gph pump cartridges fit in the 750 housing? Johnson brand in my ranger. Or is this upgrade cartridge and housing?

  11. mikesxpress
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    #11
    Mine had Rule 800 gph livewell pumps and the 1100 gpm was a drop in for the existing housings. I did a complete R&R on both the automatic and manual bilge pumps and went to Johnson. I do believe the manual Johnson bilge pump housing accepts multiple pump gpm pump sizes up to 1000 gpm with the 3/4" discharge.

  12. mikesxpress
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    #12



  13. Member mikesjet's Avatar
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    #13
    Thanks Mike!

  14. mikesxpress
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    #14
    Your welcome Mike.
    If I can provide information that can help someone, then it's worth my time to offer it up.

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    #15
    Nice tutorial Mike! Thanks for sharing.

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    #16
    Thanks Mike your post and help greatly appreciated! Made my change out manageable.
    Wayne

  17. mikesxpress
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    #17

  18. mikesxpress
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    #18
    As noted above you will need to upgrade fuses to match the larger gph pumps. With more gph for the livewell you can reduce the cycle on time.

  19. mikesxpress
    Guest
    #19
    I've had some inquiries as to the source of the red protector tips shown on my hose clamps:
    Those hose clamp tail tips sure keep the clamp ends from cutting up your hands. Part#125015 from http://awabllc.com 100 pack

  20. Member
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    #20
    OK now, lets get back to fishing. What color Senkos did you use to catch all those fish Mike?
    Last edited by HalBrown; 04-28-2019 at 10:43 AM.

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