1955 Johnson 5.5 hp converted to single fuel line with pump puking oil or carbon

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  • April 26, 2026 at 9:47 am #316519
    DickS

      out of the exhaust and coating lower case.  What am I doing wrong other than running too rich?

      April 26, 2026 at 11:37 am #316522
      seakaye12
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        Is your pump diaphragm ruptured?

        When you squeeze your primer bulb there should be NO flow out of the vacuum pulse line.

        April 26, 2026 at 12:12 pm #316528
        RICHARD A. WHITE
        Participant

          Lifetime Member

          This is a 2-stroke, you WILL have a certain amount of unburnt fuel/oil mixture seeping. It can only be stopped by never running your motor.
          So you need to make a decision, run it and accept it, or buy a 4-stroke.
          The modern 2 cycle oil is designed to have much less environmental impact than regular motor oil used when the motor was new.

          http://www.richardsoutboardtools.com
          classicomctools@gmail.com

          April 26, 2026 at 12:25 pm #316530
          seakaye12
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            Which fuel pump are you using for your motor?  2-Stroke engines produce a stronger crankcase pulse than the typical 4-stroke engine does.

            Many of the ultra-cheap fuel pumps on the market are copies of lawnmower type 4-stroke pumps and have been known to fail on 2-stroke applications.

            If this happens…..raw fuel is pumped directly into the crankcase through the pulse line.

            Can you post a picture of your pump?

            April 26, 2026 at 5:03 pm #316561
            JACQUES
            Participant

              all these motor also have a dump route  to flush accumulated  fuel oil mix pooling inside the crankcase…

              IF  the  purge route/ valve  is blocked,   purge channels blocked  by your mod.to pump     etc… fuel oil  micx piles up in the crankcase especially at idle.

              you need to run wot and the stuff will be ingested back into the cylinders  but keep in mind that when “in ports”  open incoming fuel oil juices  also shoot  out the “exhaust ports” & 30-40%  fuel-oil  gets dumped directly out by  the bad  2 stroke design. at $4G US or 8$cdn it get expensive to be so wasteful.   my  75hp  ETEC burns .6 l of fuel/h trolling 🙂

              A 0.6-liter amount goes into one imperial gallon about 7.6 times so in theory I can troll   at least 7 hours  on 160 oz of fuel.

              for a US gallon 128 oz.. A 0.6-liter amount goes into one U.S. gallon about 6.3 times…..so figure 6 hours  trolling

              I doubt you could troll 6-7 hours with a 5.5 hp    with 1 gallon !!

               

               

               

              Joining AOMCI has priviledges 🙂

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