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    Fuel delivery-gctid359042

    Seems I need some input. I have to crank the engine a pretty long time, several 5-10 second bursts for the float bowl to fill. Cause the evaporated fuel from sitting is making me want the elec fuel pump, I decided to poke around the engine bay. My fuel filter assy is mounted higher than the fuel tank / supply hose, more than half way up the center of the actual tank. If I use an elec pump (the Carter pump mounts in the same location as the mechanical), will I possibly have a problem? Electric fuel pumps, are they not "pusher" pumps, not pullers of fuel? Relocation of the fuel filter is a possibility.

    #2
    Jim, It is true that these do a better job at pushing, rather than pulling. However, if you use the Carter style electric fuel pump, elevation (within normal limits), should not be an issue. This pump is capable of pulling through the filter media just as the mechanical pump is.

    If the fuel filter is at a slightly higher elevation than the fuel tank is, once the system is primed, the elevation is no longer a concern. Doubt this will be an issue anyway.

    Note that with the electric fuel pump, you must have the power circuit interruptible via a N/O oil pressure switch.

    This is a USCG regulation.

    This is to interrupt the fuel pump power in the absense of engine oil pressure.

    It also means that the pump will not operate until power is applied via the oil pressure switch, will be open until pressure comes up.

    This oil pressure switch can trigger a relay.... of which I'd also prefer.

    A relay is also much easier to connect in the next topic here and less likely to pose any back-feed issues.

    So.... you need a means of operating the fuel pump prior to oil pressure.

    Two ways to do this:

    A.... starter motor circuit by-pass that operates the pump relay during cranking only. Cannot be capable of any back-feed.

    B.... momentary helm switch that operates the pump relay during the switch operation only. Must be momentary.

    I like B in that you control when the pump turns on to prime the system. No engine cranking necessary.

    Saves battery power and, in theory, should extend the starter motor life some.
    Rick E. Gresham, Oregon
    2850 Bounty Sedan Flybridge model
    Twin 280 HP 5.7's w/ Closed Cooling
    Volvo Penta DuoProp Drives
    Kohler 4 CZ Gen Set

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      #3
      penguin wrote:
      Seems I need some input. I have to crank the engine a pretty long time, several 5-10 second bursts for the float bowl to fill. Cause the evaporated fuel from sitting is making me want the elec fuel pump, I decided to poke around the engine bay. My fuel filter assy is mounted higher than the fuel tank / supply hose, more than half way up the center of the actual tank. If I use an elec pump (the Carter pump mounts in the same location as the mechanical), will I possibly have a problem? Electric fuel pumps, are they not "pusher" pumps, not pullers of fuel? Relocation of the fuel filter is a possibility.
      Did your system always act this way?

      My engine didn't require this much cranking at start up after a winter's nap. It sounds like there must a problem in the fuel delivery system somewhere..........
      2005 2359 Trophy Pro "SOLD"
      "Amigo"
      B lll 5 ltr.
      1998 2452 (Sold) "Island Time"

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        #4
        Thank you both. I'll check the delivery. There is a real old style filter in line with a racor. I posted this up several months ago, plan on removing it. That may contribute to a supply issue, unsure.

        I'll be putting in the momentary prime switch at the helm as advised. Now I'm off to order 2 fuel pumps, relays, and pressure switches from Summit Racing.

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