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What Oil Weight should I use ???????

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  • What Oil Weight should I use ???????

    I have a 1990 Regal 233 XL Ambassador (Cabin Cruiser Type) - carburated Mercruiser 5.7 (350 ci). I live near the border of Missouri & Arkansas, all lake water use. I would like to know what weight and brand of oil to use. I've had a number of people tell me straight 40 or 30, 10-40 or 10-30 and use mobile1. Mostly I heard straight 30 for Northern boats and straight 40 for Southern. Thanks to all that reply!


  • #2
    Re: What Oil Weight should I use ???????

    10w-30 is the most commonly used for any small block
    28' Carter Safari, Twin Mercruiser 255MIE
    http://forums.iboats.com/showthread.php?t=281698

    Comment



    • #3
      Re: What Oil Weight should I use ???????

      Hmm,


      You missed yesterdays oil thread! Your's can be today's Seems like this question is asked about every day or so.....


      If you do not want to use the oil that Mercury recommends,

      You can use what ever you want. Marine engines don't fail due to brand or type of oil. Everything has been tried successfully.


      Cheers,


      Rick
      ----------------------------------------------------------------------------------
      I use xxx oil and have never had a problem........
      This post was created with OpenSuSE x64 Linux!

      Comment



      • #4
        Re: What Oil Weight should I use ???????

        Merc says their 25/40 or straight 40...
        I would not use a 10w-30 in a marine inboard...more likely to break down...as long as your boating temps are moderate the straight 40 will be fine...
        OMC and Volvo recommended straight 30....Merc straight 40 for the same base engines...go figure...
        1988 Four Winns 200 Horizon
        4.3 OMC Cobra

        98 Jeep Grand Cherokee 4.0 Selectrac
        07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

        "While air doesn't freeze....rust never sleeps"

        Comment



        • #5
          Re: What Oil Weight should I use ???????

          Originally posted by Lou C View Post
          Merc says their 25/40 or straight 40...
          Well, Mercruiser has a few more choices than that. And the straight 40 or straight 30 depend upon the temp....


          Comment



          • #6
            Re: What Oil Weight should I use ???????

            Now I'm confused????????
            Weather temps would be around 70-99 degress.
            I'd be running 15-20 minutes at a time.
            I'm thinking straight 40.
            Any other opinions, please advise!
            Thank you

            Comment



            • #7
              Re: What Oil Weight should I use ???????

              Originally posted by Johnny Be Cool View Post
              I'm thinking straight 40.
              That'll work just fine.

              Comment



              • #8
                Re: What Oil Weight should I use ???????

                just use straight 40
                Wrap it up b!

                Comment



                • #9
                  Re: What Oil Weight should I use ???????

                  Anything from straight 40 on up the chart to other options listed. Straight 40, according to Merc, is the 4th best option.
                  Checkmate 2400BRX/Optimax 300xs
                  .
                  Alumacraft 17 w/ Merc 40 4S

                  Date an I/O, but marry an outboard!©

                  Comment



                  • #10
                    Re: What Oil Weight should I use ???????

                    Originally posted by Johnny Be Cool View Post
                    I have a 1990 Regal 233 XL Ambassador (Cabin Cruiser Type) - carburated Mercruiser 5.7 (350 ci). I live near the border of Missouri & Arkansas, all lake water use. I would like to know what weight and brand of oil to use. I've had a number of people tell me straight 40 or 30, 10-40 or 10-30 and use mobile1. Mostly I heard straight 30 for Northern boats and straight 40 for Southern. Thanks to all that reply!
                    I use 10-40 on all motors and never had a problem. Great in all kinds of weather. Use a top notch brand.

                    Comment



                    • #11
                      Re: What Oil Weight should I use ???????

                      Tomorrow it is my turn to ask this question.
                      sigpic
                      It isn't easy being GREEN

                      Comment



                      • #12
                        Re: What Oil Weight should I use ???????

                        Just my 2 cents. In my 30+years as a GM master tech, all the classes I've been to, GM was very insistant not to use 10w40 in any of their engines. There a ton of 350 GM engines out there in boats. Unlike a car engine, boat engines run at a continuosly higher rpm. I would recommend the 30 or 40 weight oil that the service manual says. It is very unlikely that you operate your boat engine in below freezing temps, so the need for the 10w oil in multi viscosity oils isn't needed. Remember 10w30, the w stands for winter

                        Comment



                        • #13
                          Re: What Oil Weight should I use ???????

                          Thanks to all for giving your opinions.
                          I'm thinking of staying with a straight 30 or 40, therefore what is the difference between the two and their applications.
                          Under what circumstance should I run 40 or 30 weight.
                          Thank you!!!!

                          Comment



                          • #14
                            Re: What Oil Weight should I use ???????

                            30 is going to be less thick when cold. if you are always boating with temps well above freezing go with either 30 or 40.
                            I would stick with a diesel grade oil, in a 30 or 40 weight. you will not have any trouble.

                            Comment



                            • #15
                              Re: What Oil Weight should I use ???????

                              Go Figuire???????????
                              Mercruiser suggested Quick Silver 25w-40 or straight 30
                              I appreciate everyone's opinion. Thank You and Happy boating!!!!!!!!!

                              Comment

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