Announcement

Collapse
No announcement yet.

5.0l feels like its running out fuel

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

    5.0l feels like its running out fuel

    One of my engines will not stay running 5.0l 2 bbl carb. I just put the boat in 2 weeks ago and ran it a couple of times with no issues. Last weekend while the boat was at idle in neutral the engine stalled, it cranked a bit to restart but was ok after than and it ran fine on plane and at idle after that. Today I went to warm up the boat with the throttle opened a little bit to warm it up and I noticed the rpms were starting to drop slowly from 2k and finally the engine stalled. I was messing with it some more and it will idle for a few seconds and then the rpms just slowly go down again and it stalls. It will rev up fine when cracking the throttle, no hesitation at all and it will hold a 3k+ rpm but does fluctuate down a few hundred rpm and then goes back up and this is abnormal. After a few more minutes messing with it, now fully warmed up when I get to 2k pulling the throttle back slowly it just shuts off. It sounds like it is running out of fuel. Hard to restart also, need to pump the throttle a bit. I did not want to leave the dock to see if it will hold a load because I only had my kids with me and docking would be tough on 1 engine.

    The only thing I have tried so far is eliminating the tank and running it off of a gas can but it had no change in the way it ran.

    I don't believe there is an easy way to check fuel pressure, so I am thinking its a carb or pump issue. Does this sound like a fuel issue, coil?? I want to start to swap some parts form the good engine but would like some thoughts on what would be the best thing to try first.
    1999 3055, 5.0L, Bravo 2

    #2
    Have you changed your fuel filters? There is the spin on and one where the fuel line connects to the carburetor.
    P/C Pete
    Edmonds Yacht Club (Commodore 1993)
    1988 3818 "GLAUBEN”
    Hino EH700 175 Onan MDKD Genset
    1980 Encounter Sunbridge "Misty Blue" (Sold)
    MMSI 367770440
    1972 Chevrolet Nova Frame off Resto-mod in the garage
    Boating on the Salish Sea since 1948

    Comment


      #3
      Sorry the other thing I did check it the filter in the neck of the carb and it is clean. I have not removed the spin on fuel/water separator filter but do have one sitting here ready to change. I will do that as soon as I get a chance to.
      1999 3055, 5.0L, Bravo 2

      Comment


        #4
        You have electric fuel pumps that get power from an oil pressure switch which can go bad. Sounds like a low rpm the switch is opening removing power from the fuel pump and the engine stalls once the carb runs dry.
        1997 Maxum 2400 SCR 5.7LX Bravo II

        Mike

        Comment


          #5
          Mike, Is this switch separate from the OP switch for the alarm and gauge because the low OP alarm works fine. If it is a separate switch where is it and can I just throw a jumper wire in it to force the pump to run?
          1999 3055, 5.0L, Bravo 2

          Comment


            #6
            Originally posted by vogs77 View Post
            Mike, Is this switch separate from the OP switch for the alarm and gauge because the low OP alarm works fine. If it is a separate switch where is it?
            Yes it is a separate switch. The alarm has its own and the oil pressure gauge uses a separate sender. The switch for the fuel pump should be mounted next to the alarm switch just above the oil filter block mount. If you have a remote oil filter it’s where the adapter is on the engine block.
            1997 Maxum 2400 SCR 5.7LX Bravo II

            Mike

            Comment


              #7
              I am heading down not to look at that now, I do not have remote oil filter, it is still located on the bottom of the block.
              1999 3055, 5.0L, Bravo 2

              Comment


                #8
                Originally posted by vogs77 View Post
                I am heading down not to look at that now, I do not have remote oil filter, it is still located on the bottom of the block.
                The fuel pump switch will have 2 wires on where the alarm switch only has 1 wire.
                1997 Maxum 2400 SCR 5.7LX Bravo II

                Mike

                Comment


                  #9
                  The newer version of that switch comes with a different plug but the new plug comes with the switch. Don’t get thrown off because it’s called a kit. If you look down carefully past the aft end of the port exhaust manifold you should be able to see the switch. I found that the Mercruiser part was actually less than an aftermarket. Go figure.
                  P/C Pete
                  Edmonds Yacht Club (Commodore 1993)
                  1988 3818 "GLAUBEN”
                  Hino EH700 175 Onan MDKD Genset
                  1980 Encounter Sunbridge "Misty Blue" (Sold)
                  MMSI 367770440
                  1972 Chevrolet Nova Frame off Resto-mod in the garage
                  Boating on the Salish Sea since 1948

                  Comment


                    #10
                    So I think it's too much fuel, not lack of. I just left the boat and was watching in the throat of the carb on the properly running engine and it has great atomization if the fuel. When I watch inside if the bad engine the fuel is dripping heavily into it and I believe flooding it below 2k rpm. Back probed purple power wire with it running and battery voltage present at all times when running. I think it's carb rebuild time.
                    1999 3055, 5.0L, Bravo 2

                    Comment


                      #11
                      You can swap carbs to see if it follows the carb but I think you’re right time for a rebuild
                      1997 Maxum 2400 SCR 5.7LX Bravo II

                      Mike

                      Comment


                        #12
                        Yup, you have a sticky float valve. You might think about having both rebuilt. If you are in the Puget Sound Area, I recommend Carb Connection in Kirkland. They did the carbs on my previous boat and dialed in my muscle car resto-mod.
                        P/C Pete
                        Edmonds Yacht Club (Commodore 1993)
                        1988 3818 "GLAUBEN”
                        Hino EH700 175 Onan MDKD Genset
                        1980 Encounter Sunbridge "Misty Blue" (Sold)
                        MMSI 367770440
                        1972 Chevrolet Nova Frame off Resto-mod in the garage
                        Boating on the Salish Sea since 1948

                        Comment


                          #13
                          I already lost 1 weekend in our short boating season this year I am going to try to find a quality rebuilt one to just slam on and go and have the other one rebuilt and install it on the other motor. Any recommendations on who sells a good rebuilt one would be great.
                          1999 3055, 5.0L, Bravo 2

                          Comment


                            #14
                            Originally posted by vogs77 View Post
                            So I think it's too much fuel, not lack of. I just left the boat and was watching in the throat of the carb on the properly running engine and it has great atomization if the fuel. When I watch inside if the bad engine the fuel is dripping heavily into it and I believe flooding it below 2k rpm. Back probed purple power wire for the fuel pump with it running and battery voltage present at all times when running. I think it's carb rebuild time.
                            Oops just trying to fix my post #10 from earlier
                            1999 3055, 5.0L, Bravo 2

                            Comment


                              #15
                              Is this your carb? https://www.i-5automotive.com/produc...rb-carburetor/

                              If yes, I have one I do not need: https://www.baylinerownersclub.org/f...-carb-for-sale

                              Comment

                              Working...
                              X