1959 Evinrude 18hp Miss/Stutter?

Home › Forum › Ask A Member › 1959 Evinrude 18hp Miss/Stutter?

Viewing 10 posts - 1 through 10 (of 14 total)
1 2
  • Author
    Posts
  • September 25, 2018 at 12:34 pm #11335
    shane-r13
    Participant

      I have the above stated motor a 1959 Evinrude 18-hp. I just recently got it so I am working my way through gremlins replacing as I go.

      Currently having an issue with it missing/stutter when I start it. This happens right away as soon as its running. I thought maybe it was sucking air. I have replaced all the fuel lines on the motor side, also replaced the vacuum line on the motor side. The new fuel line is a clear/blue and I don’t see any air bubbles in the lines when running. I also replaced the o-rings on my fuel connector from the tank as the fuel one would leak slightly when pressurizing the tank. Didn’t help my issue but it did stop leaking. I think getting a video and posting what it is doing would be helpful. Unfortunately i wont have time today to do that.

      Side note as well, when I pressurize my tank , the thumb primer gets hard as it should, when I start the motor and run it and it miss/stutters than dies after a minute or so. I goto prime the tank and its no longer hard. No super soft by any means but I can prime it 5-8 times before becoming hard. Is the tank seals or something maybe an issue?

      Do anyone know what the probable cause could be? or what to check? is it even a fuel related issue? I haven’t even dug into the electrical as I hadn’t gotten there yet and it starts and runs wonderful minus the miss/stutter it has.

      Any leads or pointers as always appreciated!

      Shane

      September 25, 2018 at 1:07 pm #83510
      lindy46
      Participant

        If it’s starting and running, it’s probably not a fuel delivery issue. First you say "it miss/stutters than dies after a minute or so". Then later you say it runs fine aside from the stutter. Which is it? The primer button doesn’t pressurize the tank, it only pumps gas into the carb to get it running. Then the engine does the job of pressurizing the tank. You should hear a hiss when loosening the gas cap after the motor has been running. If you do, then it’s not a fuel delivery problem. But if you have to push the button to keep it running, then it’s a fuel delivery issue. You could have a lean-sneeze – adjust the slow speed needle by turning counter-clockwise to richen up the fuel to air mixture. If that doesn’t help, it could be a dirty carb or fuel filter. (have you rebuilt the carb?) or an ignition problem – bad coil, points (or dirty points), condenser or a plug wire intermittently shorting out.

        September 25, 2018 at 2:38 pm #83515
        shane-r13
        Participant

          Hi thanks for the reply. I guess i did contradict myself. It runs buts misses or stutter, if i increase throttle it will run longer but eventually dies out. If
          I don’t increase throttle it dies faster. I do have pressure when losing the gas cap, so by your explanation that means my fuel system should be working. I will have to try backing the slow speed needle out more. I have taken the carb apart and inspected and it was clean looking. But have not rebuilt it. I plan too just wanted to figure out this issue before digging into that. The fuel filter has been removed currently to lessen things that the problem could be.

          Does anyone have the OHMs for the coil and condensers?

          I’ll have to dig into the electrical system i guess.

          Thanks,
          Shane

          September 25, 2018 at 3:00 pm #83516
          frankr
          Participant

            US MEMBER PAY BY CHECK

            Lean sneezing after startup is normal and expected. But it will be worse if the slow speed needle is set too lean. Once warmed up a bit and properly adjusted, the sneezing should stop. Another "normal" thing is you may have reprime the tank a time or two to keep it running until sufficient pressure has built up. This is particulary true if the tank doesn’t have much fuel in it.

            Coil primary winding is around an Ohm, secondary is around a "few" K-Ohms. They vary. Depends on the maker of the coil. If they are cracked, they are junk, no matter what you measure. Condenser is 0.22 mfd capacitance.

            EDIT: Capacitance corrected.

            September 25, 2018 at 7:14 pm #83526
            shane-r13
            Participant

              Thanks for the numbers Frank. My tank is currently about half full. I’ll have to try backing out my slow speed screw, then on to the electronics i suppose.

              Thanks,
              Shane

              September 27, 2018 at 12:32 pm #83597
              shane-r13
              Participant

                Maybe I found the culprit? Waiting on my Flywheel removal tool to come in the mail tomorrow to swap it out.

                Attachments:

                September 27, 2018 at 12:58 pm #83598
                lindy46
                Participant

                  Yup, those coils are shot. I’m surprised it ran at all.

                  September 27, 2018 at 1:11 pm #83600
                  shane-r13
                  Participant

                    Yes, I’m hoping that is the only issue. I one spare of each coil, condenser, and points. So hopefully changing this side out does the trick. The other coil looks brand new so I hope its still good since i currently don’t have a spare laying around.

                    October 1, 2018 at 2:42 pm #83803
                    shane-r13
                    Participant

                      So i changed out the coil on the one side that was bad. I also put a new float in the carb and cleaned it. Still having an issue with it stuttering. I noticed now i have air in fuel line when it dies, the air makes it was back towards the built in filter. I’ve uploaded a video to youtube and hopefully my link works and maybe someone seeing what its doing will have a suggestion.

                      Shane

                      https://www.youtube.com/watch?v=dxjE7by … e=youtu.be

                      October 1, 2018 at 2:53 pm #83806
                      frankr
                      Participant

                        US MEMBER PAY BY CHECK

                        That clearly is sneezing due to running too lean and / or running out of gas. I had to listen to it a couple of times before realizing the horrible rattle at the end is because the lower cowling has busted mounts.

                        First thing you need to address is can you keep it running by pressing the tank primer button? Related to that is does the tank build up pressure? Once you have established you are getting sufficient fuel from the tank, adjusting the slow speed needle may fix the sneezing.

                      • Author
                        Posts
                      Viewing 10 posts - 1 through 10 (of 14 total)
                      1 2
                      • You must be logged in to reply to this topic.