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So.... how do I fix this???-gctid363440

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    #16
    FYI, those blue plugs simply do not last very long. They tend to dry out and get brittle with time due to engine heat. My engines are only 5 years old and already I have had 2 leaks. I strongly suggest you replace with new ones every 3 years or so. I keep extras in my tool box along with the o-rings. Mine were easily removed with a screw driver shoved into the hole. Ideally a brass wing nut plug would solve the replacement issue but I have yet to find one.
    Cheers, Hans
    2007 Carver 41 CMY
    Twin Volvo D6-370
    Montreal, Canada
    Midnight Sun I Photos

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      #17
      The plugs are threaded 1/2" 13 tpi UNC, do not use a pipe thread tap as you will destroy the thread in the tapped hole and never be able to fit a standard blue plug again.

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        #18
        lexdavis wrote:
        The plugs are threaded 1/2" 13 tpi UNC, do not use a pipe thread tap as you will destroy the thread in the tapped hole and never be able to fit a standard blue plug again.
        Correct you are. The plugs seal via the o-ring and not like conventional NPT threads. More like o-ring boss style or ORB if you prefer.

        Just to clarify things a little. If your engine is newer and have blue plugs there are straight thread ORB. If they are steel or brass plugs on an older engine they are tapered or NPT if you prefer.
        Cheers, Hans
        2007 Carver 41 CMY
        Twin Volvo D6-370
        Montreal, Canada
        Midnight Sun I Photos

        Comment


          #19
          lexdavis wrote:
          The plugs are threaded 1/2" 13 tpi UNC, do not use a pipe thread tap as you will destroy the thread in the tapped hole and never be able to fit a standard blue plug again.
          Whether tapered or straight......., my suggestion was to Chase the threads.... as in clean them up from any plastic debris......... not re-cut them!
          Rick E. Gresham, Oregon
          2850 Bounty Sedan Flybridge model
          Twin 280 HP 5.7's w/ Closed Cooling
          Volvo Penta DuoProp Drives
          Kohler 4 CZ Gen Set

          Comment


            #20
            I have never seen these things but replacing them with a brass plug be an option? It would eliminate all of this.

            Doug
            Started boating 1955
            Number of boats owned 32
            Bayliners
            2655
            2755
            2850
            3870 presently owned
            Favorite boat. Toss up. 46' Chris Craft, 3870 Bayliner

            Comment


              #21
              Not really Doug as you need to remove them every year to winterize. If you winterize without removing the plugs ala antifreeze running method it is still a good idea to open these up to rinse sediment out very year or so with the wire poke method we all mention. Personally my engines have 9 per engine and these blue plugs are wing nuts hand tight which is a breeze to remove/install. The alternative is paste or teflon tape and tools in impossible positions if you know what I mean. However, yes a tapered npt plug will seal fine in a non tapered hole assuming thread TPI is the same.
              Cheers, Hans
              2007 Carver 41 CMY
              Twin Volvo D6-370
              Montreal, Canada
              Midnight Sun I Photos

              Comment


                #22
                Not wanting to sound like a smart a## here but you guys need to check a thread chart before offering these suggestions.

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                  #23
                  2850Bounty wrote:
                  Whether tapered or straight......., my suggestion was to Chase the threads.... as in clean them up from any plastic debris......... not re-cut them!
                  The problem is fixed.... thanks for the suggestion to Rick & Lex.

                  By the way, just to confirm, threads are 1/2 x13NC

                  Comment


                    #24
                    MidnightSun wrote:
                    Not really Doug as you need to remove them every year to winterize. If you winterize without removing the plugs ala antifreeze running method it is still a good idea to open these up to rinse sediment out very year or so with the wire poke method we all mention. Personally my engines have 9 per engine and these blue plugs are wing nuts hand tight which is a breeze to remove/install. The alternative is paste or teflon tape and tools in impossible positions if you know what I mean. However, yes a tapered npt plug will seal fine in a non tapered hole assuming thread TPI is the same.
                    I never meant not to remove them Hans. Many engines use brass plugs that you remove every year.

                    I often replaced the plugs with petcocks which has wing nuts which made it easier.

                    Doug
                    Started boating 1955
                    Number of boats owned 32
                    Bayliners
                    2655
                    2755
                    2850
                    3870 presently owned
                    Favorite boat. Toss up. 46' Chris Craft, 3870 Bayliner

                    Comment


                      #25
                      lexdavis wrote:
                      Not wanting to sound like a smart a## here but you guys need to check a thread chart before offering these suggestions.
                      Actually, whomever is shoving the tap in the hole needs to determine what the thread is. Just like whomever puts a wrench on a nut needs to determine what size wrench to use.

                      And other people looking at thread charts isn't going to do that.

                      Comment


                        #26
                        mdldgl wrote:
                        The problem is fixed.... thanks for the suggestion to Rick & Lex.

                        By the way, just to confirm, threads are 1/2 x13NC
                        So these are 1/2" machine threads, not tapered nor straight pipe threads! Hmmm.

                        Well, glad that you sorted it out.
                        Rick E. Gresham, Oregon
                        2850 Bounty Sedan Flybridge model
                        Twin 280 HP 5.7's w/ Closed Cooling
                        Volvo Penta DuoProp Drives
                        Kohler 4 CZ Gen Set

                        Comment

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