1941 Neptune Muncie Carb

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  • April 30, 2021 at 3:36 pm #237455
    NeptuneMadness
    Participant

      Hey friends, I finally got my 41″ Neptune completed, full rebuild restoration. I attempted to fire it up today and no luck. ^%&%%!!! I got it to “Cough” twice, but just nothing. The carb is getting fuel, but my sparkplug was dry. I got a new rebuild kit for it, and 99% certain I put it back together correctly. I have to take it apart and look over it, but would anyone have any suggestions? I have plenty of compression, new gaskets and seals.

      I wasn’t expecting to really Start! But that cough gave me so much hope! Hasn’t ran in over 60 years, so back at it!

      Thanks friends!

      April 30, 2021 at 5:12 pm #237463
      Buccaneer
      Participant

        US Member

        If you squirt some gas in the spark plug hole and quick put the plug back in,
        will it fire then? At least that might tell you if your spark under compression
        is okay.

        Is the motor sitting normally like it would on a boat transom?

        Prepare to be boarded!

        April 30, 2021 at 6:14 pm #237465
        NeptuneMadness
        Participant

          I used starter fluid, but that’s when it coughed, I am wondering, where the fuel line goes into the Carb, I had to use 2 washers, cause their is a good sized gap with out them, from the screw to the side. and fuel was dripping, I wonder if I have a vacuum leak. Not sealed well enough.

          Yep, motor was up and down like it would be on a boat. I’m thinking my coil isn’t strong enough anymore too, but at the moment I want to tackle why the fuel isn’t reaching the plug. then worry about the coil.

          Thank you my friend!

          April 30, 2021 at 7:39 pm #237467
          Buccaneer
          Participant

            US Member

            Is your compression adequate?
            You say full rebuild, what have you done to the ignition?
            Might be helpful for others if they knew what model / HP motor you’re talking about too.

            Prepare to be boarded!

            April 30, 2021 at 7:52 pm #237468
            NeptuneMadness
            Participant

              Its a 1941 Neptune Muncie 1.5hp model 11B1

              Oh yeah, you turn the fly wheel it pushes your thumb out the spark plug hole. Yup, New rings, Honed, rebuild carb, new spark plug wire, No chance finding a coil or points for that, but you hold the spark plug wire and it bites!

              But Im thinking, it might be just a hair weak to power a spark plug, the spark is a little weak.

              April 30, 2021 at 9:37 pm #237474
              NeptuneMadness
              Participant

                I pulled the Carb off, to double check the reed, make sure it wasn’t backwards! haha, It is a bit stiff, but I put my hand over the intake hole, and its not STRONG suction, I don’t know HOW much is really needed to open the reed, But I am kinda wondering if I might possibly have a compression issue.

                April 30, 2021 at 10:20 pm #237476
                jcrigan
                Participant

                  US Member

                  See if you can find looseness in the top crankshaft bushing. Many times that causes a lean mixture. Wiggle the flywheel.

                  1 user thanked author for this post.
                  NeptuneMadness
                  April 30, 2021 at 10:26 pm #237477
                  BRIAN RUPP
                  Participant

                    There should be some decent suction on intake. Check that the reeds close completely and not crooked. Mine only went on one way as thd machining is rough on these motors. Try some gas in the spark plug and see if it will go. Mine has a walbro carb, and is trouble to get going sometimes. Spark should jump a 1/4″ – 3/8″ gap. Make sure points are clean and .020 gap.

                    April 30, 2021 at 11:10 pm #237478
                    NeptuneMadness
                    Participant

                      Hi Brian, the suction isn’t bad, I can feel it suck my hand in a bit if I cover the intake hole, with the carb off. but it’s not super strong. The reed has a good snug closure, Im wondering if it isn’t flexing enough to allow fuel in. Yup, I have a walbro carb too. The spark isn’t bad.. it does give a small bit if you put finger in plug boot and turn the flywheel. this no fuel reaching plug is what really has me baffled.

                      Thank you for your time! and Help!

                      May 1, 2021 at 9:53 am #237483
                      BRIAN RUPP
                      Participant

                        Ok. If you can stick a screw driver in plug wire clip and it jumps min 1/4 -3/8 inch your spark is good enough. Next steps: Make sure the pulse port going to the carb is clear all the way to the crankcase, and oriented to the carb correctly. Next make sure the pulse port on the carb is clear to the diaphram. I did that on a chainsaw carb swap once, couldn’t figure why it didn’t run correctly….. oops! If all that is well and the carb is clean and in good shape, give it a prime of gas in the spark plug and it should light up. If all that fails, turn the high and low speed jets out 2 turns total. It will draw only light air at hand speed turning fly wheel. Thr reed plate gasket isn’t made wrong and catching the reeds it it? It is possible that some one rebuilt the carb and put the wrong choke butterfly in there. I had a Mono 48 saw that needed the choke plate to cover 95% to start it. Any less and not enough suction to opperate the Lauson Power Products carb.

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                        NeptuneMadness
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