help with compression

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  • irtrimble
    Senior Member
    • Oct 2004
    • 31

    help with compression

    Engine won't start, of course. i probably cranked it too long with water intake open. When I check compression, no compression on cylinders 1 and2, a trace in cylinder 3, and good compression in 4 but spit out a lot of water. Head gasket vs flooded manifold? I closed water intake, put some lightweight oil in all cylinders, cranked it some, and am letting it sit. Any ideas?
  • Mo
    Afourian MVP
    • Jun 2007
    • 4468

    #2
    Check the oil and see if there are signs of water there...grey oil, bubbles on dipstick, increase level. A little more history on the engines last time running would help. Did it overheat, how long was it sitting without being started, how was it running etc.
    Mo

    "Odyssey"
    1976 C&C 30 MKI

    The pessimist complains about the wind.
    The optimist expects it to change.
    The realist adjusts the sails.
    ...Sir William Arthur Ward.

    Comment

    • irtrimble
      Senior Member
      • Oct 2004
      • 31

      #3
      was slow to start but ran smoothly for 20 minutes while I charged battery. four or five days later, just wouldn't catch at all, with some grey water inside spark arrestor. Will check oil tomorrow.

      Comment

      • sastanley
        Afourian MVP
        • Sep 2008
        • 6986

        #4
        Don't let the cylinder walls get rusty..make sure you spray/squirt oil in there, and keep the feedback from our Q's coming.
        -Shawn
        "Holiday" - '89 Alura 35 #109
        "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!)
        sigpic

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        • JOHN COOKSON
          Afourian MVP, Professor Emeritus
          • Nov 2008
          • 3500

          #5
          What make and model of boat? Catalina 30?

          TRUE GRIT

          Comment

          • irtrimble
            Senior Member
            • Oct 2004
            • 31

            #6
            C & C Redwing 30

            Comment

            • irtrimble
              Senior Member
              • Oct 2004
              • 31

              #7
              Oil does indeed look gray. I drained it and will change it again. Still only have compression on #4, although I can see some valves moving in other cylinders when I crank it.

              Comment

              • irtrimble
                Senior Member
                • Oct 2004
                • 31

                #8
                Changed oil a couple of times with oil getting clear. Still no compression on cylinders 1, 2, 3. I figure I'm looking at an engine teardown/rebuild. Much as I would like to use Moyer Marine, the logistics of getting an engine back and forth from Chester, Nova Scotia to Maryland seem forbidding. Does anyone on the South Shore of NS have a recommendation for a local shop?

                Comment

                • tenders
                  Afourian MVP
                  • May 2007
                  • 1440

                  #9
                  With known water intrusion and bad behavior in three cylinders, I'd take the head off to assess all valves, cylinders, and head gasket. Worst case, you've got a head start, so to speak, on the necessary rebuild. Best case, the situation is contained and you're only out a head gasket and whatever stud complications arise.

                  Comment

                  • edwardc
                    Afourian MVP
                    • Aug 2009
                    • 2491

                    #10
                    With water incursion confirmed, the likelyhood of sticking valves being the culprit is pretty high. So, before you pull the head, I would try freeing the valves. Its easy but can take a lot of time. The idea is to get lubrication to the valve stems from both ends.

                    For the lower end, add a quantity of Marvel Mystery Oil (MMO) to the final oil change. You can replace as much as 1 quart of oil with MMO. I regularly run with 4 oz of MMO in the oil as a preventitive measure.

                    For the upper end, pull the spark plugs and squirt some MMO into the cylinders. Try to get an old-style oilcan with a long skinny nozzle to direct the oil towards the valves. Replace the plugs (without wires) to contain any mess from ejected oil and turn the engine over several times, either by hand or using the starter, to distribute the oil. Do this once or twice a day for several days. Then recheck the compression. Repeat as necessary. When/if you start getting compression back in 2 or 3 cylinders, try to start it. It will start hard and smoke as the MMO burns off, and run rough, but running should help work loose the last if the sticking valves.
                    @(^.^)@ Ed
                    1977 Pearson P-323 "Dolce Vita"
                    with rebuilt Atomic-4

                    sigpic

                    Comment

                    • irtrimble
                      Senior Member
                      • Oct 2004
                      • 31

                      #11
                      Thanks. Will keep lubricating and cranking.

                      Comment

                      • irtrimble
                        Senior Member
                        • Oct 2004
                        • 31

                        #12
                        removing head not a possibility, at least not for me! MMO not available but have tried some lightweight 2 cycle oil
                        Attached Files

                        Comment

                        • Peter
                          Afourian MVP
                          • Jul 2016
                          • 296

                          #13
                          Originally posted by irtrimble View Post
                          Does anyone on the South Shore of NS have a recommendation for a local shop?
                          I have had a lot of luck getting parts from the fellows at Nova Automotive in HRM.

                          Peter

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