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1987 johnson GT150 V/6 power problem

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  • 1987 johnson GT150 V/6 power problem

    Hello all, My J150GTLCUR 150GT has been giving me troubles, It starts fine but once
    I go to throttle it up above 1/4 throttle it boggs and just won.t take off.So Heres where
    I'm at! I have rebuilt all three carbs to the core! found lower carb had cracked tubes
    in the bowl the ones that have calabration holes,I replace the carb but did not help.
    Then I had replaced the primer bulb but used a cheap one which never got firm.So then
    I replaced it with a OMC bulb,replace all fuel lines and I mean All! even the water sep,filter.even the valves in both gas tanks that have the balls that keep fuel from draining back to tank check valves.drained and cleaned both gas tanks,still bogging!
    Then I replaced the VRO pump with new lines as well.with the new pump and OMC primer
    bulb the bulb gets very firm now. tryed it this morning and still bogging.the gas tank vents are clean. comp. is and always was 92 lb's on all 6 cly's hot or cold! Not even 1 pound deffrent. I see when I fire it up in the lake it cranks easy. idels great at first then
    as I take off it seems to had sputered a few times and then the motor idels up and if I throw it in neturel= it runs up near 2500 to 3000 rpms. so sort of a runaway idel?
    Thought at first it was starving for fuel and leaning out but I have cleaned!rebuilt! and changed everything as said above. the only thing I have not done is a spark test and thats comming tonight. I pulled all plugs just now after running it at the ramp and they
    all 6 look wet and the same . any help plzz.

  • #2
    Re: 1987 johnson GT150 V/6 power problem

    you need to slow down with the parts changing until you isolate your problem. sounds like possibly a linkage issue or timer base problem, you need to check timer base for sticking, do a link and sync, check all linkage and cables. I will assume all carb connections are sealed and no problem with sucking air.
    Free ignition troubleshooting guide http://www.cdielectronics.com/techni...ort-documents/
    You will need a DVA adapter http://www.usatoolwarehouse.com/usat...e/ESI-640.html First test compression, Second test spark with a spark gap tester set a 7/16 gap, Third check timing, next CLEAN your carbs properly,

    Comment


    • #3
      Re: 1987 johnson GT150 V/6 power problem

      carbs are sealed tight! I was thinking from the start it was a air leak and or carb rebuild. So now the whole fuel system is
      ok, with the eratic idel and the bogging it seemed to be a air leak and lean condition. Link and sinc done. have moved throttle
      back and fourth and timer base moves freely. I have really replaced fuel related parts and weeks later into this a VRO pump
      thinking it might had been weak. When I found the lower carb with the cracked tubes I said! Thats the prob, It was not!

      Comment


      • #4
        Re: 1987 johnson GT150 V/6 power problem

        fixing the carb tubes was fine...but replacing the VRO on a guess was a little costly, you can test them pumps. anyway it almost has to be a timing or sucking air or linkage issue..only 3 problems that I know of that will cause run away idle. since it is sparatic I would tend to eliminate sucking air, and focus on linkage and timing. does pumping the bulb help any??? one more thing, are all your needle valves sealing up tight..maybe one is sticking open..next time it has the problem, remove the carb cover and look and see if a carb is flooding, this could cause boggy and over idle.
        Free ignition troubleshooting guide http://www.cdielectronics.com/techni...ort-documents/
        You will need a DVA adapter http://www.usatoolwarehouse.com/usat...e/ESI-640.html First test compression, Second test spark with a spark gap tester set a 7/16 gap, Third check timing, next CLEAN your carbs properly,

        Comment


        • #5
          Re: 1987 johnson GT150 V/6 power problem

          I agree on the sucking air deal as it is sparatic so to speak, It's kind of you to help me here and I thank you for that.
          as far as pumping the bulb it changes nothing, And the needles and seats there on the money. New kits in all three carbs
          and when fliped can't blow air threw them.and the new primer bulb gets hard very firm.even mounted the bulb in a upright
          angle where the ball valve can work. My boat mach.. friend said for me to mark the flywheel on all cyl's top dead center
          and then useing a timeing light to make sure the mark of the cyl. i'm checking don't change as theres a chance of the
          powerpacs double fireing? I will test the spark and timing as you said. again thanks Sparkieboat

          Comment


          • #6
            Re: 1987 johnson GT150 V/6 power problem

            I have the exact same engine as yours when this bogging above 1/4 throttle happened to me it was only one thing and that was the high speed jets were clogged up and had to be recleaned. 2 hours time and good to go; maybe take a look at them again. Who knows?

            Comment


            • #7
              Re: 1987 johnson GT150 V/6 power problem

              Will I guess your right even though I just had them off a week ago who knows? I removed every jet and cleaned and sprayed and run wire thru them. But whats weard I can push the key in when it's bogging and zoom zoom i'm off. still like a lean prob but i,ve changed everything related to fuel.

              Comment


              • #8
                Re: 1987 johnson GT150 V/6 power problem

                OK did spark test! port side has a bright 7/16 spark, the starboard side has none,had 1 cyl spark a tad but not a blue spark!
                this 1987 johnson 150GT has two power pac's I think theres one on each side? I even put a spark plug in the three starboard side
                wires and even then a weak spark,

                Comment


                • #9
                  Re: 1987 johnson GT150 V/6 power problem

                  you can try switching the power packs and see if problem follows...to do a real test of electronics you need to get a DVA adapter and go to CDI electronics web site in the support section there is a free trouble shooting guide...that all needs to get fixed before you can go any further
                  Free ignition troubleshooting guide http://www.cdielectronics.com/techni...ort-documents/
                  You will need a DVA adapter http://www.usatoolwarehouse.com/usat...e/ESI-640.html First test compression, Second test spark with a spark gap tester set a 7/16 gap, Third check timing, next CLEAN your carbs properly,

                  Comment


                  • #10
                    Re: 1987 johnson GT150 V/6 power problem

                    So your saying unbolt the power pac's and move them side to side?

                    Comment


                    • #11
                      Re: 1987 johnson GT150 V/6 power problem

                      Yes. This will let you know if the issue is with the power pack or with the timer base, coils or stator. It can also be a loos conection on you kill wire to the power pack. But these power packs are known for failure due to high heat condition on these motors. I would swap the power packs sides to side. Make sure you ground out the packs (bolting them down when checking). If the condition swaps sides then it is you power pack. If it does not, swap your coils, and recheck, If still nothing then you will need the DVA tester and a service manual like Sparkieboat suggested.

                      Repost your results
                      J Bisson
                      ___________________________

                      Current Boats
                      1993 Lund Pro V 1775 Tiller - 75 hp Mariner & 4 hp Johnson Sail Master
                      1963 Sears 14' Utility - 9.9 Mercury (For Sale)

                      Past Projects
                      https://forums.iboats.com/showthread.php?t=521563https://forums.iboats.com/showthread.php?t=443915
                      https://forums.iboats.com/showthread.php?t=457212

                      Past Boats
                      1991 Bayliner Trophy 2002 WA
                      1971 Starcraft Chieftan 21
                      1981 Lund Utility
                      1961 Evinrude Tri-Hull

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                      • #12
                        Re: 1987 johnson GT150 V/6 power problem

                        I understand, I'll do the swap and see what happens. I'll first ck grounds, I hope i'm getting close to fixing this thing LOL
                        So thanks again for your help everyone.

                        Comment


                        • #13
                          Re: 1987 johnson GT150 V/6 power problem

                          Ok swaped the power packs and the port side still fireing great and starboard not! so power pack that was not working before swap
                          works now. Now i'm guessing both power packs are good? so must be something under the flywheel right? that feeds the packs.

                          I heard a stator is eather good or bad! so what eles feeds the power packs?

                          Comment


                          • #14
                            Re: 1987 johnson GT150 V/6 power problem

                            Is it called a OMC TIMER BASE - 6 CYL. 133-3377

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                            • #15
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                              Re: 1987 johnson GT150 V/6 power problem

                              Yes it is the timer base that feeds the signal to the power pack to fire. The stator supplies that power to fire and there is still the shift interupt switch that kills one of the sides power packs in order to shift. Also the same wire plugged into the power pack is along with (same wire) the kill switch (fall over board laynard switch).

                              I would unplug the yellow black wire to both power packs and see if it will run. Caution though. You will not have a way to turn off the motor with out re plugging in the wires. They are the kill switches to turn off the motor.

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                              I found this wiring diagram on the web here. It is supposed to be a 1986-87 evinrude diagram. Check it out. See if it helps you.
                              J Bisson
                              ___________________________

                              Current Boats
                              1993 Lund Pro V 1775 Tiller - 75 hp Mariner & 4 hp Johnson Sail Master
                              1963 Sears 14' Utility - 9.9 Mercury (For Sale)

                              Past Projects
                              https://forums.iboats.com/showthread.php?t=521563https://forums.iboats.com/showthread.php?t=443915
                              https://forums.iboats.com/showthread.php?t=457212

                              Past Boats
                              1991 Bayliner Trophy 2002 WA
                              1971 Starcraft Chieftan 21
                              1981 Lund Utility
                              1961 Evinrude Tri-Hull

                              Comment

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