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  1. #1

    Default BF50D Fuel pump issue

    Hello,

    Got my boat in the water yesterday and on its mooring. Went out today and was just about past the harbor and it spluttered and died. Had my friend tow me back to the mooring.

    The primer bulb was soft and I notice no noise now when I turn the ignition on like the pump isnt engaging, going to check the pump fuse later today when tide is out.

    I cleaned the vapor separator and changed the high pressure fuel filter before putting her out. I noticed people had replaced the pump so was going to just replace it but I cannot find a replacement pump anywhere. Anyone know where I can buy one for my engine?

    Thanks in advance

  2. #2
    Join Date
    Sep 2008
    Location
    Hague, Virginia, USA
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    4,826

    Default Re: BF50D Fuel pump issue

    Go to www.boats.net, "Honda Outboards" and find your engine model & SN range, pull up the parts diagram and that will give you the part number and their purchase price. I find that they have about the best prices around and fast shipping.
    CHawk 25 DLX

  3. #3
    Join Date
    Sep 2008
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    Hague, Virginia, USA
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    Default Re: BF50D Fuel pump issue

    However, check your fuses and wiring first. Honda fuel pumps are pretty rugged and seldom fail IMO.
    CHawk 25 DLX

  4. #4

    Default Re: BF50D Fuel pump issue

    Chawk,

    Thanks for the advice.

    Quick update:

    Went out today fuse looked fine. Turned it over and boom fired up no issues. Couldnt leave it running as was low tide so no water so just cut it right out again.

    This is the second time this has happened seemed to be around the exact same running time also around 20 minutes or so, 10 min warm up and 10 min running around 3k revs going out the harbor. (second time ive had to get towed home!)

    Wondering if its getting flooded automatic choke or something?

    Going to go out at high tide tomorrow and let it tick over on the mooring for half an hour and see if it happens again.

    My fuel tank was stolen last year from the back of the boat while in the drive way only seems to have happened since I put the new smaller one not sure if it could be anything to do with that, but it appears that after it cuts out and is left for some time it starts again first time.

    Thanks again.

  5. #5
    Join Date
    Sep 2008
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    Hague, Virginia, USA
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    Default Re: BF50D Fuel pump issue

    Well, don't get mad at me for this, but are you opening the vent on that new fuel tank? It's usually on the filler cap, but not always. If you are, try running it with the fuel cap loosened. The vent could be clogged.
    CHawk 25 DLX

  6. #6

    Default Re: BF50D Fuel pump issue

    Haha not at all any advice greatly received. Yes opened the vent but it has been sitting a year so will try loosening fuel cap tomorrow.

    Thanks again.

  7. #7
    Join Date
    Sep 2008
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    Hague, Virginia, USA
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    Default Re: BF50D Fuel pump issue

    OOPS! Was gas in the tank when it was sitting for a year? If so, get new, fresh gas and treat it with Sta-Bil or similar.
    CHawk 25 DLX

  8. #8

    Default Re: BF50D Fuel pump issue

    Yes but I binned the fuel got new stuff and added stabil. Same again today full throttle around for about 10 mins and it spluttered and died no issues at all at first.

    https://youtu.be/IGUoioy68Ic



    I tried fuel cap loosened and another fuel line from the auxiliary but wouldn't start again.
    Left it 30mins and it fired up but any kind of throttle it would stall. See below video.

    If left overnight it will go no problem for 20 min or so. Totally baffled.

    https://youtu.be/X7FRumPlE8g
    Last edited by willste01; 06-23-2020 at 03:24 PM.

  9. #9
    Join Date
    Sep 2008
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    Default Re: BF50D Fuel pump issue

    OK. Hopefully someone will jump on this that knows more about the 50's than I do. I'm beyond my level of knowledge on these engines.

    But looking at the videos, my initial thinking i that you may have an electrical problem just by seeing how suddenly it dies. That could be the electrical to the fuel pump. But it could be several other issues.
    CHawk 25 DLX

  10. #10

    Default Re: BF50D Fuel pump issue

    No worries. Thanks for all your advice.

  11. #11

    Default Re: BF50D Fuel pump issue

    Maybe a low pressure pump or low pressure fuel filter issue?

    The vapor separator holds a cup or so of fuel, that is SUPPOSED to be replenished as the high pressure fuel pump uses it. That's the low pressure pump's responsibility. If there's a restriction (like a plugged low pressure filter for instance) the low pressure pump may not be able to resupply the reservoir the high pressure pump runs in fast enough under higher fuel demands, but would be fine on idle.

    Before replacing the high pressure pump, I would want to know there is power getting to it, as well as a ground.

    Regarding sourcing a replacement high pressure pump, do a google search on the Honda part number and see what turns up. I'd go with a used Honda part prior to some of these aftermarket pumps though....

  12. #12
    Join Date
    Apr 2018
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    1,298

    Default Re: BF50D Fuel pump issue

    Have you tried using the primer bulb yo me to it going, this will give you some direction. If it keeps going you will know it's the low pressure side, if not, then high pressure. Looking at your video I would say you have a low pressure delivery problem, either a partial blockage or weak fuel pump.

  13. #13

    Default Re: BF50D Fuel pump issue

    Andy,

    I took the low pressure filter out of the vaporiser unit and it looked ok. Will take it out again and give it a good clean ( have ordered a new one). It will only run at idle for so long then it dies and wont start for a while again.

    If left over night it will go fine for 20-30 mins full throttle.

    can't seem to find the low pressure pump looking at the diagrams on boats.net only the high pressure one which is listed under vapor seperator

    https://www.boats.net/catalog/honda/...apor-separator.

    Ian,

    When its dying pumping the bulb does nothing and once its died pumping the bulb will not get it started again. When its dying / dead the bulb does go soft.

    Initially the first time I had this problem i would start to bog down if i went above 3k revs and if i brought the throttle back it would run fine.

  14. #14

    Default Re: BF50D Fuel pump issue

    Low pressure filter - Check out "F8"

    https://www.boats.net/catalog/honda/.../cylinder-head

  15. #15
    Join Date
    Sep 2008
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    Hague, Virginia, USA
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    Default Re: BF50D Fuel pump issue

    According to that diagram on www.boats.net, item 13 is the pump - PUMP ASSY., FUEL (MSDS) PN 16700-ZZ5-003
    CHawk 25 DLX

  16. #16
    Join Date
    Apr 2018
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    Default Re: BF50D Fuel pump issue

    You need to work out why this motor is running out of fuel, these low pressure pumps are good quality and very rarely fail. Start by checking fuel volume flow, disconnect the fuel tube on the delivery side of the low pressure pump located on the starboard side of the cylinder head head. Then with a container placed at the outlet use the primer bulb to pump fuel through, it should be easy to pump and the bulb should expand back to its original shape quickly. If it's hard to pump or the bulb takes time to replenish, then you have a fuel restriction to look for.

  17. #17
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    Apr 2018
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    Default Re: BF50D Fuel pump issue

    One more thing, have you ever used ethanol based fuel in this motor?

  18. #18

    Default Re: BF50D Fuel pump issue

    Hi Ian,

    Thanks for your advice. Just got back from the boat. I ran it 20 mins again till it died and tested the ignition with a spark tester good spark on all plugs so definitely not a spark issue.

    I then removed the pipe going into the low pressure fuel pump as you suggested and fuel is coming that far and the bulb returns to shape.

    I opened the vent screw on the high pressure filter after it conked to check for fuel and no fuel is reaching there after it dies even when I turn the ignition on and here the pump no fuel comes as far as the high pressure filter, so it appears to be something stopping the fuel coming from the low pressure pump to the high pressure filter.

    I tried to blow through the inward pipe on the low pressure pump with the high pressure filter vent open unsuccessfully not sure if it is a closed circuit when the pump is off as not familair with the setup.

    Doesn't seem to be very easy to remove the VST for inspection whilst in the water haha might need to bring it ashore if I cannot find the issue.

    Just weird that it runs fine for 20 minutes then will not restart but once left for a period it will run for another 20 minutes as if something is over heating!

    But there is definitely no fuel getting to the high pressure filter chamber after it dies.


    Regarding fuel have only ever put UK unleaded fuel in it nothing else.

  19. #19
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    Default Re: BF50D Fuel pump issue

    A quick and easy way to see if there is fuel in the VST is to attach a clear hose to the drain and hold up against the separator with the drain screw open and see where the fuel level is. If you have plenty of fuel then you will have to replace the high pressure pump. if not, then the low pressure pump.

  20. #20

    Default Re: BF50D Fuel pump issue

    Great idea. Will try to remember that one!

  21. #21

    Default Re: BF50D Fuel pump issue

    Thanks. There was plenty fuel in the vst looks like I will need to replace the high pressure pump.

    Its like the fuel is seeping through slowly. If I remove the pipe from the exit of the high pressure filter and wait a few mins and engage the ignition a little trickles out.

    Thanks for all the advice will wait on the pump coming and go from there.

    Can I safely remove the inlet manifold to get to the pump?
    Last edited by willste01; 06-27-2020 at 05:36 PM.

  22. #22

    Default Re: BF50D Fuel pump issue

    2 things I found recently when getting into a similar issue with one of these. First is the pump only runs for 2 seconds when the key is turned on. Why is above my pay grade. They're cutting the ground to the ground wire side of the pump in the ECU.

    The other thing, after having had the VST apart several times trying to figure the problem (suspicious of the pump as well) I found that the outlet of the high pressure pump inserts into a grommet shaped kinda like a top hat. When/if this grommet is pushed in beyond where it's supposed to sit (not that hard), the grommet blocks/fouls the small outlet hole in the casting (the hole leading to the high pressure filter). This leads to just a trickle of fuel available. I cured the issue with a 30 second trim of the grommet using a #11 xacto blade, assuring that the outlet hole in the casting will never be blocked by that grommet again.
    Last edited by Alan Hicks; 06-28-2020 at 08:33 AM.

  23. #23

    Default Re: BF50D Fuel pump issue

    Quote Originally Posted by Alan Hicks View Post
    2 things I found recently when getting into a similar issue with one of these. First is the pump only runs for 2 seconds when the key is turned on. Why is above my pay grade. They're cutting the ground to the ground wire side of the pump in the ECU.

    The other thing, after having had the VST apart several times trying to figure the problem (suspicious of the pump as well) I found that the outlet of the high pressure pump inserts into a grommet shaped kinda like a top hat. When/if this grommet is pushed in beyond where it's supposed to sit (not that hard), the grommet blocks/fouls the small outlet hole in the casting (the hole leading to the high pressure filter). This leads to just a trickle of fuel available. I cured the issue with a 30 second trim of the grommet using a #11 xacto blade, assuring that the outlet hole in the casting will never be blocked by that grommet again.
    Alan,

    I whipped out the VST today and stripped it. Decided to test the pump with water while waiting on the new one.. the plastic cover/filter that goes around the pump was distorted and twisted I tried to pump water with it connected to a car battery and nothing. I stripped it off and tried and it pumped water perfectly free from the vst. Put it back together no water coming out. I loosened it a bit back from this grommet your talking about and boom water flowing perfectly. Thinking I have maybe wasted money on a new pump haha! drying everything out now and have trimmed the rubber grommet will put back together tomorrow and find out of it was indeed this causing the issue. Will let you know.

  24. #24

    Default Re: BF50D Fuel pump issue

    Alan,

    Your a legend. Reassembled everything and just back from a 4hr trip engine running sweet. I have a spare pump on route that I don't need haha but just glad it's working.

    Can't believe it was down to that little rubber grommet!

    Thank you to everyone who offered advice and suggestions.

  25. #25

    Default Re: BF50D Fuel pump issue

    Love those happy endings!

    I'm left wondering if that grommet isn't intended to be installed on the pump then inserted into the casting vs. the opposite. Can't believe Honda would do something so silly.....

    Can't you return the pump unopened?
    Last edited by Alan Hicks; 06-30-2020 at 10:59 AM.

  26. #26

    Default Re: BF50D Fuel pump issue

    Yes it seems weird that it can do that I would never have suspected it. I might keep the pump as the plastic cover/filter that goes over the pump had severely warped and i had to give the pump a good thump to get it out thinking it was broken anyway haha so may keep as a spare should it decide to fail down the line.

  27. #27
    Join Date
    Apr 2009
    Location
    Commerce TWP, MI, USA
    Posts
    37

    Default Re: BF50D Fuel pump issue

    I have the same problem with my Honda BF50D2LRT. The motor runs great for about 15 minutes and then just dies out. Wont start. There is gas in the VST. Can you tell me where that grommet is located and what part it is on the diagram ?? Sorry to not start a new post but this is whats wrong with mine and hoping to get a quick response so IClick image for larger version. 

Name:	Honda cylinder head and fuel pumps.png 
Views:	9 
Size:	89.0 KB 
ID:	24087can fix it for the weekend.

  28. #28

    Default Re: BF50D Fuel pump issue

    Hey Buddy,

    It is on this diagram here https://www.boats.net/catalog/honda/...apor-separator

    Number 28 is the grommet it sits on top of the exit side of the fuel pump. Once you open the VST the pump is in there and when you unscrew it and pull it out the grommet is left sittiing in the housing. pull out the grommet from there and you can trim it off

  29. #29
    Join Date
    Apr 2009
    Location
    Commerce TWP, MI, USA
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    37

    Default Re: BF50D Fuel pump issue

    An update to fuel pump issue: I pulled out the VST and replaced the insulator part 16721-ZY9-003 with a new one. The new one is just a hair shorter and seems to be made of a little stiffer rubber. I cut a chunk out of the insulator on the bottom so the orifice will never be covered. You can see on the old part where it had been sucked into the orifice and was clogging the fuel when it would heat up after 15 to 20 minutes of running. Took the boat out and ran it for 35 to 40 minutes and it ran great. I understand there was was a no call recall on the issue with the insulator. I also called a Honda mechanic at the place the motor was purchased and he diagnosed it as the insulator right off the bat based on the symptoms. Thanks for your input and hope this helps others with the issue.

  30. #30

    Default Re: BF50D Fuel pump issue

    So that's 3 of us just this year that frustration I experienced has helped.....

    Surprised that issue isn't more widely known.

    Makes you wonder how many pumps are replaced without legitimate cause.
    Last edited by Alan Hicks; 07-08-2020 at 08:48 AM.

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