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replaced my fuel pump, now gas pouring out of carburetor

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  • replaced my fuel pump, now gas pouring out of carburetor

    hello everyone, i'm having a heck of a time trying to get the boat running this season and i need your help.

    background: the boat ran perfect last year and was winterized properly.

    when i tried to start up the boat this spring it sounded like it was starving for fuel. it would run rough and die at idle if i let the throttle get that low. i disconnected the fuel line going into the carb and very little fuel was coming out of the line when i cranked the engine.

    i suspected a lack of fuel and i saw several possible sources: gas tank pick up screen, fuel filter, and fuel pump. i bypassed the fuel filter and eliminated that variable--same results. unfortunately, i can't get the pickup tube out of my gas tank as there is not enough room without ripping out the floor of my aft cabin. the fuel pump is the original volvo red mechanical fuel pump with only an inlet and an outlet.

    i know people will go nuts...i replaced it with a gm automotive mechanical fuel pump with just an inlet and outlet--EXACT SAME SET UP AS MY VOLVO ORIGINAL! after i did this and fired it up, gas started pouring out of the carburetor. i didn't get to see where it was coming from as i was looking over my shoulder and couldn't pin point it.

    This leaves me with 2 possibilities that i can think of:

    the automotive fuel pump pumps too hard or fast?

    my carb float or float valve is defective?


    i haven't asked any questions here in awhile and could really use your help. please give me some wisdom. you can flame me for the auto part, too
    1986 Bayliner 2150 Sunbridge (aq225e/275)

  • #2
    Re: replaced my fuel pump, now gas pouring out of carburetor

    there is also a vent to that fuel pump. The vent hole is what make the pump work. Marine pumps have a fitting with a hose.
    This hose is called a "tell-tale" ,its lest you know the diaphragm has ruptured. Without it the gas from the ruptured diaphragm
    goes into the bilge and we read about your death in the newspaper.
    NO PERSONAL QUESTIONS, THIS IS WHAT THE FORUM IS FOR.

    Comment


    • #3
      Re: replaced my fuel pump, now gas pouring out of carburetor

      Originally posted by Bt Doctur View Post
      there is also a vent to that fuel pump. The vent hole is what make the pump work. Marine pumps have a fitting with a hose.
      This hose is called a "tell-tale" ,its lest you know the diaphragm has ruptured. Without it the gas from the ruptured diaphragm
      goes into the bilge and we read about your death in the newspaper
      .
      Ayuh,..... Agreed,..... A new fuel pump, 'n rebuild the carb,....

      Comment


      • #4
        Re: replaced my fuel pump, now gas pouring out of carburetor

        Originally posted by possum2082 View Post
        This leaves me with 2 possibilities that i can think of:

        the automotive fuel pump pumps too hard or fast?

        my carb float or float valve is defective?


        i haven't asked any questions here in awhile and could really use your help. please give me some wisdom. you can flame me for the auto part, too
        +1 with Bondo and will add, the automotive pump will pump no more volume or pressure then the marine. the marine pump just has the safety vent tube to flood the carb instead of where we might read about you in the paper as Bt Doc mentioned.
        94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
        95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
        07 Seadoo GTX
        Merc Adults Only VP Adults Only
        G-Dad always said "First Liar doesn't stand a chance"

        Comment


        • #5
          Re: replaced my fuel pump, now gas pouring out of carburetor

          Originally posted by Bt Doctur View Post
          there is also a vent to that fuel pump. The vent hole is what make the pump work. Marine pumps have a fitting with a hose.
          This hose is called a "tell-tale" ,its lest you know the diaphragm has ruptured. Without it the gas from the ruptured diaphragm
          goes into the bilge and we read about your death in the newspaper.
          i am totally good with getting a marine fuel pump. however, before i do, please tell me what's up with my old and possibly defective red volvo pump. it doesn't have the tell tale, just a weep hole it looks like. in the pic, the nipple is inlet, the block is outlet and there's a little hole and that's it. all can be seen in the pic.Click image for larger version

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          did the previous owner buy an auto and paint it red? what the heck...or is it just that old.

          btw, thanks everyone for helping me out.
          1986 Bayliner 2150 Sunbridge (aq225e/275)

          Comment


          • #6
            Re: replaced my fuel pump, now gas pouring out of carburetor

            Looks like an automotive pump to me!

            Comment


            • #7
              Re: replaced my fuel pump, now gas pouring out of carburetor

              Originally posted by MikDee View Post
              Looks like an automotive pump to me!
              that's what i was thinking.

              so, earlier when i went to the auto store to get my new one...the guy gave me one with a "tell-tale," from an 86 gm, i told him i needed 2 ports only and so we went back to 75 and found one that matched.

              can i use an fuel pump replacement auto from an 86 as long as it has the "tell tale" for safety (clear line plumbed to my carburetor of course?
              1986 Bayliner 2150 Sunbridge (aq225e/275)

              Comment


              • #8
                Re: replaced my fuel pump, now gas pouring out of carburetor

                Originally posted by possum2082 View Post
                that's what i was thinking.

                so, earlier when i went to the auto store to get my new one...the guy gave me one with a "tell-tale," from an 86 gm, i told him i needed 2 ports only and so we went back to 75 and found one that matched.

                can i use an fuel pump replacement auto from an 86 as long as it has the "tell tale" for safety (clear line plumbed to my carburetor of course?
                You can use a fuel pump so long as it has the diaphragm overflow fitting for the clear line which goes to the carburetor, like this Airtex model

                Carter M61073 Fuel Pump Marine Mechanical Chevy Small Block 5 0 5 7L Each | eBay
                Last edited by AllDodge; May 16th, 2014, 10:42 AM.
                94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
                95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
                07 Seadoo GTX
                Merc Adults Only VP Adults Only
                G-Dad always said "First Liar doesn't stand a chance"

                Comment


                • #9
                  Re: replaced my fuel pump, now gas pouring out of carburetor

                  thank you all for your help!

                  I took apart the top of my Rochester carb last night to find 2 things:

                  1. it was filled with crap (good news since I know what was causing my bad running even with the new pump).
                  2. previous owner definitely put in an auto carb along with his auto fuel pump and auto starter

                  we've been running this set up for 4 years and i'm done pushing my luck. i'll be putting on marine parts before I dip it in.

                  thanks again.
                  1986 Bayliner 2150 Sunbridge (aq225e/275)

                  Comment


                  • #10
                    Re: replaced my fuel pump, now gas pouring out of carburetor

                    You can use an auto carb so long as you can run the clear tube from the marine pump to the top of it. This way if the fuel pump diaphragm leaks the fuel goes down the carb and not in the bilge.

                    Getting a rebuilt one isn't a bad idea though
                    94 Formula 27PC Custom 509MPI MEFI3 , B3 XR
                    95 Rinker 232 w/ 7.4L Carb 0F425011 B1 0F486471
                    07 Seadoo GTX
                    Merc Adults Only VP Adults Only
                    G-Dad always said "First Liar doesn't stand a chance"

                    Comment


                    • #11
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                      Re: replaced my fuel pump, now gas pouring out of carburetor

                      Originally posted by AllDodge View Post
                      You can use an auto carb so long as you can run the clear tube from the marine pump to the top of it. This way if the fuel pump diaphragm leaks the fuel goes down the carb and not in the bilge.

                      Getting a rebuilt one isn't a bad idea though
                      doesn't my carb need a j tube to direct the flow of extra gas down the throttle?
                      1986 Bayliner 2150 Sunbridge (aq225e/275)

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