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  1. #1
    Join Date
    Apr 2011
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    Chesapeake, MD
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    15

    Default Fuel Pump Replacement - Mechanical or Electric

    I have a 307ci 210hp engine. My mechanical fuel pump needs to be replaced. I am considering replacing it with an electric fuel pump. I'm looking at the Elderbrock and Mallory marine fuel pumps. Any suggestion on a good replacement - brand, gph, psi, etc.?

    Thank you in advance for your thoughts.

  2. #2
    Join Date
    May 2007
    Location
    Kawarthas
    Posts
    3,006

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    I vote mechanical....that way you don't have to worry about any of those specs...or wiring, or new fittings....ethanol compatible hose etc
    0381764
    $185.00 $185.00
    1 in stock.
    Last edited by hystat; 04-22-2011 at 04:44 PM.

  3. #3
    Join Date
    Mar 2008
    Location
    Manalapan, nj, usa
    Posts
    3,727

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    has to be 4-7 psi no more if you have a carb.

  4. #4
    Join Date
    Apr 2011
    Location
    Chesapeake, MD
    Posts
    15

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    I've been told the electric fuel pump will provide a quicker start when the boat has been sitting for a period of time.

  5. #5
    Join Date
    Sep 2010
    Location
    Jersey Shore
    Posts
    2,953

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    Quote Originally Posted by HarMat View Post
    I've been told the electric fuel pump will provide a quicker start when the boat has been sitting for a period of time.
    I agree. I have replaced both my Mechanical pumps with electric and pretty much don't have to set the choke. Do away with the mechanical. You will have a little plumbing and electric to do.

    I have mine powered by a relay through an oil pressure switch. The pumps get straight power during engine cranking via the second small terminal on the starter. Once oil pressure comes up the oil pressure switch closes and powers a relay that powers the pump.

  6. #6
    Join Date
    Apr 2011
    Location
    Chesapeake, MD
    Posts
    15

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    These are two of the pumps under consideration. I am leaning towards the Holley only because a few years ago I replaced the original carb with a Holley.

    http://www.jegs.com/i/Holley/510/712-801-1/10002/-1

    http://www.jegs.com/i/Mallory/650/4070M/10002/-1

  7. #7

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    Quote Originally Posted by HarMat View Post
    These are two of the pumps under consideration. I am leaning towards the Holley only because a few years ago I replaced the original carb with a Holley.

    http://www.jegs.com/i/Holley/510/712-801-1/10002/-1

    http://www.jegs.com/i/Mallory/650/4070M/10002/-1
    I like the electrics also, but just a personal choice. I have, personally, had better luck w/ the Holley's than any others I have used, in my hot rodding days. Just make sure the you use the best relays and connections you can. If a cheap relay goes out, you are "dead in the water". You'll also need to add an oil pressure switch in there also, as a safety (if you didn't already know that). Not that much of an expendature to have a "spare" on board and easy to change if it does go Kaput. Plus you won't need to be concerned about a leaking pump / old diaphram squirting fuel into you oil. I'm going to convert my newly aquired 7.4L Bravo over to electric fairly soon, as the fuel pump is on the raw water pump housing, complicating water pump removal for service.

  8. #8
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    6,592

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    Ditto what Chris is suggesting, with an explanation or two.

    Quote Originally Posted by HarMat View Post
    I've been told the electric fuel pump will provide a quicker start when the boat has been sitting for a period of time.
    True, particularly if you have a means of low oil pressure switch "over-ride"...... but there's much more to this.

    With any gasoline Marine Engine electric fuel pump (for carbureted engines), the USCG (or other country equivalent) requires that the fuel pump not be allowed continued operation should the engine stall or quit.

    In comes the N/O (normally open) low oil pressure switch.

    This typically means that a start by-pass (that Chris mentions) becomes necessary during cranking. (not enough oil pressure.... no fuel)
    So yes..... circuitry and a relay!

    However, there is another means that kills two birds:
    This would be a "momentary" helm switch that would essentially over-ride the N/O oil pressure switch during cranking ONLY.
    The "key" here is that this must be "momentary" only.... (I.E., no means of being left ON)

    You would excite the electric fuel pump in order to give you what you mention in your above quote, by hitting the momentary helm switch for several seconds........
    prime the fuel bowl.....
    and away you go....
    Circuit becomes open again.....
    now you meet USCG requirements.


    I see it as a means of solving any carburetor evaporation issues, that would otherwise result from a Mechanical fuel pump.
    (i.e., crank, crank, crank......, in order to get fuel to the carb)

    I don't quite see how this would affect choke setting, however.

    .
    Rick ... aka Ricardo
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

  9. #9
    Join Date
    May 2010
    Location
    DC Burbs/Maryland Eastern Shore
    Posts
    762

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    However, there is another means that kills two birds:
    This would be a "momentary" helm switch that would essentially over-ride the N/O oil pressure switch during cranking ONLY.
    The "key" here is that this must be "momentary" only.... (I.E., no means of being left ON)

    You would excite the electric fuel pump in order to give you what you mention in your above quote, by hitting the momentary helm switch for several seconds........
    prime the fuel bowl.....
    and away you go....
    Circuit becomes open again.....
    now you meet USCG requirements.


    I see it as a means of solving any carburetor evaporation issues, that would otherwise result from a Mechanical fuel pump.
    (i.e., crank, crank, crank......, in order to get fuel to the carb)

    I don't quite see how this would affect choke setting, however.
    Well, if you do decide to install an electric fuel pump, the delay Rick refers to is relatively short. The oil pressure comes up enough in about 1 to 1 1/2 spins to start the fuel pump, so unless you have a totally bad oil pump you will never notice the delay. Most of the time the engine fires before the delay ever comes into play.
    Remember that a carb does not need pressurized fuel to operate. It draws in fuel to the engine by vacuum/venturi/Bernoulli effect, and by getting a shot from the accelerator pump. Therefore, even at zero fuel pressure the engine will start just fine if there is gas in the fuel bowl.

    I wouldn't go to the trouble of wiring up a second hot feed to the fuel pump unless you experience extremely difficult starting. I would just take a wire from the starter solenoid over to the fuel pump so that when the key was in the START position, the fuel pump would come on but as soon as the engine starts the power would come via the oil pressure safety switch.

    The other thing to remember about electric pumps...gerotor type pumps in the case of the mallory...is that they do not prime themselves. You will have to bleed or prime the pump each time that any air gets between the tank and the pump (never run your tank dry!).
    Last edited by o2batsea; 04-24-2011 at 01:30 PM.
    Practicing the ancient art of ren-ching

  10. #10
    Join Date
    Apr 2009
    Location
    Long Island, NY,
    Posts
    24

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    I'd stick with the mechanical, simple, proven, my old OMC still has the OE on it, 23 years old....

  11. #11
    Join Date
    Mar 2010
    Location
    Tx.
    Posts
    80

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    One slight snag I can see running a "prime" wire to the starter solenoid is... If the engine builds oil pressure before the engine starts then the oil pressure switch can back feed to the starter keeping the starter engaged even if you let go of the swith, it would need a diode to prevent this. Had the same problem trying to excite a 3 wire gm alternator without an oil pressure switch
    Jeff:cool:

  12. #12
    Join Date
    Sep 2012
    Location
    Escondido, CA
    Posts
    3

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    After being dead in the ocean twice because of a faulty new mechanical fuel pump, I have decided to try electric.

    Question I have is physical placement: between the fuel tank and the fuel filter/water separator, or between the fuel filter/water separator and carb?

    Rod

  13. #13
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    6,592

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    Quote Originally Posted by rodinescondido View Post
    Question I have is physical placement: between the fuel tank and the fuel filter/water separator, or between the fuel filter/water separator and carb?
    Rod, this thread is from April, 2011. Best to begin your own new thread, but since we're here..........

    This would be your typical succession:
    Fuel tank....., dip tube (fuel pick up tube)....., anti-siphon valve......., USCG approved gasoline hose to main fuel filter base......, same type hose from filter base to carburetor... or steel tubing to carburetor if the filter is engine mounted.
    I prefer to see the filter base Off-Engine (remotely located).

    Rod, be sure that you understand the low oil pressure switch and it's role in opening the fuel pump circuit in the event of low oil pressure. This switch will be a N/O Switch (normally open).
    You'll also need a "start by-pass" circuit.

    .
    Rick ... aka Ricardo
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

  14. #14
    Join Date
    Sep 2012
    Location
    Escondido, CA
    Posts
    3

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    Quote Originally Posted by RicardoMarine View Post
    Rod, this thread is from April, 2011. Best to begin your own new thread, but since we're here..........

    This would be your typical succession:
    Fuel tank....., dip tube (fuel pick up tube)....., anti-siphon valve......., USCG approved gasoline hose to main fuel filter base......, same type hose from filter base to carburetor... or steel tubing to carburetor if the filter is engine mounted.
    I prefer to see the filter base Off-Engine (remotely located).

    Rod, be sure that you understand the low oil pressure switch and it's role in opening the fuel pump circuit in the event of low oil pressure. This switch will be a N/O Switch (normally open).
    You'll also need a "start by-pass" circuit.

    .
    Sorry, I did not notice the start date.

    Thanks much for the quick response. Let me amplify/clarify a little.

    This is on a 77 SeaRay Sundancer 25 with Volvo 280 outdrive ... I think I recall it refernced as AQ265? 265 hp chev 350 conversion.

    I have 2 concerns/options regarding the physical placement of the new electric fuel pump.

    I can place it low in the bilge to insure it is below the normal fuel level; the concern is that is before the fuel filter and subject to any existing crud in the fuel tank.

    I can place it after the fuel filter (yes, all uscg certified fuel line and filter is not mounted on the engine); the concern is that the new pump would be a little higher and if there is too much restriction in the fuel filter that would affect fuel flow. Maybe I am just fretting here over nothing and this is the place to put the new pump. Because I have been around the ocean all my life I am very picky about details of my machinery before going out.

    I have the low oil pressure switch, but had not thought about the start bypass switch until reading here ... good idea.

    At least initially I intend to place a fuel pressure regulator and gauge somewhere before the carb.

    Thanks again for the help.

    Rod
    Last edited by rodinescondido; 09-10-2012 at 07:00 PM.

  15. #15
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    6,592

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    Quote Originally Posted by o2batsea View Post
    1... Remember that a carb does not need pressurized fuel to operate. It draws in fuel to the engine by vacuum/venturi/Bernoulli effect, and by getting a shot from the accelerator pump. Therefore, even at zero fuel pressure the engine will start just fine if there is gas in the fuel bowl.

    2... I wouldn't go to the trouble of wiring up a second hot feed to the fuel pump unless you experience extremely difficult starting. I would just take a wire from the starter solenoid over to the fuel pump so that when the key was in the START position, the fuel pump would come on but as soon as the engine starts the power would come via the oil pressure safety switch.
    1... His Volvo Penta AQ260 is likely fitted with a Rochester Quadra-jet. If so, these are prone to evaporating the fuel bowl when sitting for any length of time. The momentary helm switch is the Cat's Meow for priming the fuel bowl prior to any engine cranking.
    Key word: "Momentary" helm switch.
    Why crank and crank when the momentary by-pass helm switch solves this problem?
    You'll end up extending the life of the starter motor, and your battery bank will undergo a lessor amount of deep cycles.

    Doesn't sound like much..... but multiply this over the years of long cranking required to get fuel into the fuel bowl.


    2... A relay needs to be brought into the system in order to prevent a back-feed to the starter motor's solenoid S terminal.
    Otherwise, once the pump is powered (via the oil pressure switch), power may continue to energize the S terminal via electrical current back-feed.


    Quote Originally Posted by kountzelightdiesel View Post
    One slight snag I can see running a "prime" wire to the starter solenoid is... If the engine builds oil pressure before the engine starts then the oil pressure switch can back feed to the starter keeping the starter engaged even if you let go of the swith, it would need a diode to prevent this. Had the same problem trying to excite a 3 wire gm alternator without an oil pressure switch
    Or.......... a relay brought into the loop.
    The momentary helm switch powers the slave side of the relay..... not the solenoid circuit.
    Conversely, the solenoid circuit also momentarily powers the slave side of the relay.

    Once this circuit lets go of the relay, all returns to normal, and the fuel pump will continue to operate as long as there is oil pressure above the switch's NO (normally open) pressure setting.


    Quote Originally Posted by rodinescondido View Post
    Let me amplify/clarify a little.

    This is on a 77 SeaRay Sundancer 25 with Volvo 280 outdrive ... I think I recall it refernced as AQ265? 265 hp chev 350 conversion.

    I have 2 concerns/options regarding the physical placement of the new electric fuel pump.

    I can place it low in the bilge to insure it is below the normal fuel level; the concern is that is before the fuel filter and subject to any existing crud in the fuel tank.

    I can place it after the fuel filter (yes, all uscg certified fuel line and filter is not mounted on the engine); the concern is that the new pump would be a little higher and if there is too much restriction in the fuel filter that would affect fuel flow. Maybe I am just fretting here over nothing and this is the place to put the new pump. Because I have been around the ocean all my life I am very picky about details of my machinery before going out.

    I have the low oil pressure switch, but had not thought about the start bypass switch until reading here ... good idea.

    At least initially I intend to place a fuel pressure regulator and gauge somewhere before the carb.
    Rod, I'd take that Volvo Penta OEM engine mounted fuel filter, and toss it in the recycle bin.
    This OEM filter arrangement is not a good design by today's standards.
    Instead, purchase yourself a Parker/RACOR system, and remotely locate it OFF Engine, and first in line immediately after the fuel tank pick up and anti-siphon vavle.
    Use the latest USCG approved gasoline fuel hose.


    BTW, I believe that you can find a mounting plate that allows the new electric pump to mount in the same location as the mechanical pump.
    The plate blocks off the oil cavity, and of course the push rod would be removed.

    As for a pressure regulator..... what makes you think that this is necessary? Just curious.
    As for a pressure gauge installed in a gasoline fuel pump system, you'd best check to see this would be USCG approved.
    Rick ... aka Ricardo
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

  16. #16
    Join Date
    Sep 2012
    Location
    Escondido, CA
    Posts
    3

    Default Re: Fuel Pump Replacement - Mechanical or Electric

    Quote Originally Posted by RicardoMarine View Post
    1... His Volvo Penta AQ260 is likely fitted with a Rochester Quadra-jet. If so, these are prone to evaporating the fuel bowl when sitting for any length of time. The momentary helm switch is the Cat's Meow for priming the fuel bowl prior to any engine cranking.
    Key word: "Momentary" helm switch.
    Why crank and crank when the momentary by-pass helm switch solves this problem?
    You'll end up extending the life of the starter motor, and your battery bank will undergo a lessor amount of deep cycles.

    Doesn't sound like much..... but multiply this over the years of long cranking required to get fuel into the fuel bowl.


    2... A relay needs to be brought into the system in order to prevent a back-feed to the starter motor's solenoid S terminal.
    Otherwise, once the pump is powered (via the oil pressure switch), power may continue to energize the S terminal via electrical current back-feed.


    Or.......... a relay brought into the loop.
    The momentary helm switch powers the slave side of the relay..... not the solenoid circuit.
    Conversely, the solenoid circuit also momentarily powers the slave side of the relay.

    Once this circuit lets go of the relay, all returns to normal, and the fuel pump will continue to operate as long as there is oil pressure above the switch's NO (normally open) pressure setting.


    Rod, I'd take that Volvo Penta OEM engine mounted fuel filter, and toss it in the recycle bin.
    This OEM filter arrangement is not a good design by today's standards.
    Instead, purchase yourself a Parker/RACOR system, and remotely locate it OFF Engine, and first in line immediately after the fuel tank pick up and anti-siphon vavle.
    Use the latest USCG approved gasoline fuel hose.


    BTW, I believe that you can find a mounting plate that allows the new electric pump to mount in the same location as the mechanical pump.
    The plate blocks off the oil cavity, and of course the push rod would be removed.

    As for a pressure regulator..... what makes you think that this is necessary? Just curious.
    As for a pressure gauge installed in a gasoline fuel pump system, you'd best check to see this would be USCG approved.
    Current installation is with aftermarket fuel/water filter mounted on bulkhead away from engine and mechanical fuel pump on engine.

    I have the block-off plate to cover the mech fuel pump hole now.

    I got a little out of sequence with my thinking ... I would install a fuel pressure gauge between the new fuel pump and the carb just to make sure the pressure is ok then add pressure regulator if necessary.

    I understand the concerns regarding the fuel pressure gauge on a gas engine. I have not been able to find my ideal of an electrical sending unit and remote gauge ... at least for what I am willing to pay.

    I have a very intermittent problem where the engine slows down and quits rather quickly then after a short period will run again. I am suspecting it is the backflow preventer in the fuel tank, but a pressure gauge will tell me to look that direction or in the carb (or in the mechanical fuel pump that I intend to be gone before I splash the boat again).

    again, thanks much for the help

    Rod

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