Electric fuel pump on carb motor

Discussion in 'Gas Engines/Drives/Transmissions/Props' started by MHorn0817, Jan 24, 2023.

  1. MHorn0817

    MHorn0817 Active Member

    141
    May 16, 2021
    Bowie, MD
    1998 215 Express Cruiser
    2011 260 Sundancer
    5.7 Mercruiser Thunderbolt w/Alpha I
    350 Mag MPI w/Bravo lll
    We have a 1998 Sea Ray 215ec with 350 carb thunderbolt ignition. We are finally letting it go to a friend since we've gotten our 2011 260 Sundancer.

    When we bought the 215, the previous owner installed an electronic fuel pump. I never found a good way to get the boat to fire right up. Sometimes it would, sometimes it would need to crank for 10 seconds, sometimes I'd need to crank and stop and crank again and it starts. It always starts, just not right away like I would like. I would like to try and figure this out before our friend takes it.

    Before we bought the boat, the previous owner was always able to fire it right up. I asked his trick, a few times. He said he always just turns the key on for 10 seconds before starting it. I've done 0, 5, 10, 15 seconds and nothing recreates a immediate fire up.

    Does anybody have any ideas what it could be? I've read electric fuel pump set up can be funny on a carb motor. Should I have to pump the throttle or no? Does the choke still need to be hooked up? Could it be some other underlying issue?

    Any help and/or ideas would be much appreciated. Thank you in advance.
     
  2. hughespat57

    hughespat57 Well-Known Member

    Sep 25, 2016
    Rock Hill, SC
    300 Sundancer 1994, trailered tri-axle LoadRite roller
    Mercruiser 5.7 260HP Alpha One Gen II, twin
    I have twin 5.7/350 carbs, mechanical pumps. I replaced both pumps in 2016 and overhauled the carbs. If the boat sits particularly after running o while (hot) carbs will tend to boil off the gas and the bowls will be low or dry after a few days. They will need to be cranked a good 30 seconds to refill, then pause, pump once and then they will usually start right up.

    Carbs will never start as easy as your MPI after sitting, just one of the advantages of fuel injection.
    Before assuming a pump issue check the carbs over (especially if it runs well after starting and at WOT)
    Yes, you need the choke to be working properly. Remove the flame arrestor, be sure its clean. Cold check that the choke sets properly with one pump of the throttle. If not fix that first. When you pump the throttle be sure you get a nice spray of fuel if not the bowl could be dry or the accelerator pump could be worn out. Crank it a bit to be sure the bowl fills up and try pump again.

    The electric pumps for carbs are not usually finicky. They should be specifically for carbs, low pressure 5-6 psi only no more.
    Now it may depend how the previous owner wired it. If straight to the ignition it should cycle with the key. But unlike a car or MPI where the computer controls it, it may run continuously. If a relay or oil pressure switch is in line it may only pump when the engine has oil pressure and/or when actually cranking. In a boat this is the preferred safest configuration. So it will not keep pumping if the engine fails to start or if it shuts down for any reason even if the key is left on.

    [​IMG]
     
    Nater Potater and Flyer5 like this.
  3. Flyer5

    Flyer5 Well-Known Member SILVER Sponsor

    218
    Dec 2, 2022
    Finger Lakes NY
    1987 Sea Ray 410
    454 Crusaders
    Does the fuel pump run when you turn the key on without cranking the engine. There should be a relay that would run the pump for a few seconds. That may be bad.
     
  4. MHorn0817

    MHorn0817 Active Member

    141
    May 16, 2021
    Bowie, MD
    1998 215 Express Cruiser
    2011 260 Sundancer
    5.7 Mercruiser Thunderbolt w/Alpha I
    350 Mag MPI w/Bravo lll
    Thank you for the replies and help. It'll be a couple weeks until I get to the boat so I'll have to wait until then to check out what you guys suggested because I do not remember off hand.
     

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