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1975 70hp evinrude wont fire after carb rebuild

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  • 1975 70hp evinrude wont fire after carb rebuild

    I have been playing around with this engine for a while now
    when i first got it i tried to start it well the floats where messed up so i decided to rebuild the carbs

    1.it did run for a few seconds before the rebuild it back fired out the exhaust
    then flooded
    2.I then checked for spark good on all cylinders
    3. checked compression good and even on all cylinders about 125psi
    4. rebuilt carbs
    5.replaced fuel pump just in case
    6.tried to start
    7.seems like no gas is getting to plugs they are bone dry
    8.now gas is starting to spit out the front of the carbs

    all most like the is no crankcase vacum

    any help with this would be great

    thanks Bob

  • #2
    Re: 1975 evinrude wont fire after carb rebuild

    you could have a intake leak and check the timing is their fuel coming from the carb jets?


    what type of carb? make and modal
    Last edited by Fisher freak; June 29th, 2010, 07:56 PM. Reason: more tips
    If there isnt a manual....redneck it.

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    • #3
      Re: 1975 evinrude wont fire after carb rebuild

      What are we working on?

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      • #4
        Re: 1975 evinrude wont fire after carb rebuild

        carb
        If there isnt a manual....redneck it.

        Comment


        • #5
          Re: 1975 evinrude wont fire after carb rebuild

          1975 Evinrude what? Gas flooding out the front of your carbs sounds like floats hung open.Are you sure theyre opening and closing/seating properly?Did you do link and sync after the rebuild?
          sigpic
          DONT FORGET TO PUT THE PLUG IN!!HAPPY MOTORING
          BOATS:HOLES IN THE WATER,ALL YOUR MONEY GOES IN.GOTTA LOVE EM

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          • #6
            Re: 1975 evinrude wont fire after carb rebuild

            sorry forgot the hp 70
            model number 70573 e

            Comment


            • #7
              Re: 1975 70hp evinrude wont fire after carb rebuild

              i checked the float level 3 times and made sure they where not binding before putting it back together

              all linkage hooked up exactly how it came apart

              will have to check to see if the jets are sqruiting

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              • #8
                Re: 1975 70hp evinrude wont fire after carb rebuild

                bump

                Comment


                • #9
                  Re: 1975 70hp evinrude wont fire after carb rebuild

                  Bob,
                  I have this engine as well. Carefully check routing of the fuel line from pump to middle carb. It can get pinched between silencer and the engine if not careful. When you look you'll see an opening in the silencer for the hose. I made my fuel line a little extra long so it's not kinked at the carb and allows enough length to route through the opening in the silencer body. This is an awesome engine when running correctly, Good Luck...
                  Jon

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                  • #10
                    Re: 1975 70hp evinrude wont fire after carb rebuild

                    After putting the bowls back on the carbs,did you blow into the fuel intake with the carb right side up[and you could blow through it]and then turn the carb upside down and blow into it[you shouldnt be able to blow through it as the float/ needle valve should be closed],,,, if you can blow through it while upside down,your float is catching on something,gasket,inside of bowl,pivot pin might have a catch on it,,or the needle valve has trash in it,or needle valve could be mis aligning with the seat.,,,,so there are quite a few things that can cause float problems,,,,also one overlooked simple thing,,,make sure the spring that holds your needle valve to your float is holding the needle valve snuggly to the bottom of the float to insure it is moving right and tight with it.
                    sigpic
                    DONT FORGET TO PUT THE PLUG IN!!HAPPY MOTORING
                    BOATS:HOLES IN THE WATER,ALL YOUR MONEY GOES IN.GOTTA LOVE EM

                    Comment


                    • #11
                      Re: 1975 70hp evinrude wont fire after carb rebuild

                      update:
                      got it to fire up today just wont stay running
                      i think i will look into the floats again
                      and i think i may have a coil pack that may not be 100%

                      thankyou everyone for your help

                      i will keep anding updates on progress

                      Bob

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                      • #12
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                        Re: 1975 70hp evinrude wont fire after carb rebuild

                        update

                        well she does run now but cant keep her running
                        it seems like it breaks up when you rev it

                        the spark seems alittle weak

                        think i may try a power pack next

                        sound like a good idea


                        thanks Bob

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