neptune

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  • July 28, 2021 at 3:44 pm #243815
    David C
    Participant

      need some help on my 1937 ob12a neptune.Got it back together have spark and gas but it wont fiire.50 to 55 psi is all i can get after honing cylinder? Rings feel sharp? Thanks Dave R

      July 28, 2021 at 7:35 pm #243825
      The Boat House
      Participant


        That is too low.
        Did it run before you honed the cylinder?
        Why did you hone the cylinder?
        What was the compression before you honed the cylinder.
        Honing a cylinder and putting the old rings
        back in only lowers the compression as the
        rings are no longer seated.

        Tubs

        July 31, 2021 at 4:31 am #244002
        jcrigan
        Participant

          Remove magneto and spark plug. Squirt oil into carb and spark plug hole. Hook an electric drill to the nut on the crankshaft. Turn the motor over with the drill for 5-10 minutes, making sure you squirt oil into the spark plug hole and carb occasionally. This should help reseat the rings. If this don’t help improve compression, check ring gap and ring side clearance.

          • This reply was modified 2 years, 8 months ago by jcrigan.
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