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Merc oil vs Mobil 1

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  • Merc oil vs Mobil 1

    In a GM Mercruiser what are the thoughts on using Mobil 1 over the synthetic Mercury oil? Is it really necessary to drive 3 hours to find 5 quarts of Merc juice when I can get Mobil 1 a lot easier? If so what weight is recommended and is Merc oil really better for my engine?


  • #2
    Re: Merc oil vs Mobil 1

    Howdy,

    There's no end of people asking the same question......just do a search in this forum.....


    Here's the official answer http://www.mercurymarine.com/service...eloil.php#1124

    If you don't like that answer, then use any oil out there. Just change it once a year at the end of the boating season....

    Cheers,


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

    Comment



    • #3
      Re: Merc oil vs Mobil 1

      I don't believe that Merc owns it's own oil refinery. They just buy the oil from whoever & put a Merc label on it. It's called marketing. So, go with the Mobil. I'm not sure on the weight as you didn't post what setup you have. But, probably straight 30.

      Comment



      • #4
        Re: Merc oil vs Mobil 1

        I don't know if they make a straight 30w in synthetic. I was thinking more in line with the 15-50w high revving racing oil.

        Comment



        • #5
          Re: Merc oil vs Mobil 1

          Merc sells SAE 25W-40. Volvo Penta sells SAE 30. Both are the same GM engines. GM said to use 5W-30 back then when it was in their vehicles.
          Personally I think the engine will rust away long before it fails because of what oil your using. Use whatever you want. My humble opinion.

          Comment



          • #6
            Re: Merc oil vs Mobil 1

            15-50w high revving racing oil.
            50W oil is a bit thick for engine oil, especially if you live outside of florida or texas, and especially for an engine that rev's relatively low.

            I used to own Triumph TT that called for Triumph Racing 4T 15W-50 racing oil at 12 bucks a quart... It was nothing more than mobile with a blue triumph logo on it. But that engine redlined at 16.5K RPMS (yes you read that right) and lived most of it's live at 8K and above.
            I also used to own a heavily modified ford taurus SHO with a yamaha V6 engine. That sucker would pull through 13K, I also ran 15-50 in that.
            Your boat engine rev's on average 4500 RPMS peak... you'll be fine with a 30 or 40 weight base stock oil.
            just because you found it that way... doesn't mean it's supposed to be that way.

            Part of diagnostics is spending time figuring out not only what the problem is, but also sorting through what it isn't.

            The older the engine is, the chances of it having more than 1 problem goes up exponentially

            Boating has always been a rich mans hobby. Buying a new boat gets cheaper every year, but the maintenance, the repairs, and the overall cost of ownership of a boat has never gotten any cheaper.

            Comment



            • #7
              Re: Merc oil vs Mobil 1

              Originally posted by JustJason View Post
              50W oil is a bit thick for engine oil, especially if you live outside of florida or texas, and especially for an engine that rev's relatively low.

              I used to own Triumph TT that called for Triumph Racing 4T 15W-50 racing oil at 12 bucks a quart... It was nothing more than mobile with a blue triumph logo on it. But that engine redlined at 16.5K RPMS (yes you read that right) and lived most of it's live at 8K and above.
              I also used to own a heavily modified ford taurus SHO with a yamaha V6 engine. That sucker would pull through 13K, I also ran 15-50 in that.
              Your boat engine rev's on average 4500 RPMS peak... you'll be fine with a 30 or 40 weight base stock oil.
              I had a 2001 TT also. I always used the Mobil 1 Racing 4 (no T) from Autozone. I now have the 2006 Daytona 675. It calls for the same oil and now the Mobil 1 at Autozone says "4T". Not really sure what changed in it. It's still about $10/quart though.

              I have always wondered why the recommended oil for a given engine (made by GM) will have a different oil recommendation based on what drive is mounted BEHIND the engine. Heck, I think the oil cap on my engine even says 5w-30 even though the manual for the engine (Mercruiser) says 25w-40.
              20' Suntracker Pontoon

              Comment



              • #8
                Re: Merc oil vs Mobil 1

                Dont marine engine oils have anti rust additives which may not be present in automotive oils like Mobil 1?

                Comment



                • #9
                  Re: Merc oil vs Mobil 1

                  Nothing can rust when covered in pure motor oil so I would have to say that pretty much all oil is anti corrosive.

                  Comment



                  • #10
                    Re: Merc oil vs Mobil 1

                    Originally posted by fossill View Post
                    GM said to use 5W-30 back then when it was in their vehicles.
                    Be careful with this statement as this has more to do with fuel efficiency and beating the competition for ratings on the sticker, heck some are recommending 0W30 now. Marine engines, and generally loafing automotive engines, do not live in the same environment or deal with the same loads, speeds etc . . .
                    Keep the faith!!! We'll be back stronger than ever

                    Comment



                    • #11
                      Re: Merc oil vs Mobil 1

                      ditto on be careful regarding the thinner oils in particular... the engines spec'd to run those have differenc clearances. you would prefer a boat to have larger bearing and piston clearances and run thicker oils...

                      just don't get down hard on it until it comes up to temp - especially with thicker oils. I run mobile 1 15-50 in my boat... of course it's built a little loose....

                      Just about ANY oil that is checked often and changed regularly is better then the very best oil that isn't changed, etc...
                      Just another moron with a computer and too much time on his hands...

                      typical rainy afternoon on the river... http://www.youtube.com/watch?v=8Izi3v75jTs

                      more recent, amateur camera operator for sure!... http://www.youtube.com/watch?v=EHoXsQc6644

                      Comment



                      • #12
                        Re: Merc oil vs Mobil 1

                        Straight 30 weight.Rotella has always been a good oil.Sold at most any auto parts store or truck stop in SAE 30. About 12 bucks or so a gallon.
                        sigpic

                        1981 ChrisCraft 210 Scorpion K,175 Johnson SeaHorse

                        Comment



                        • #13
                          Re: Merc oil vs Mobil 1

                          Originally posted by Simoniz View Post
                          Dont marine engine oils have anti rust additives which may not be present in automotive oils like Mobil 1?
                          Several years ago the NMMA decided to come up with a spec for "marine" oil.

                          Go to http://www.nmma.org/certification/pr.../oils/fc-w.asp for more info.

                          They probably focused more on outboard engines than marinized automotive engines.....
                          ----------------------------------------------------------------------------------
                          I use xxx oil and have never had a problem........
                          This post was created with OpenSuSE x64 Linux!

                          Comment



                          • #14
                            Re: Merc oil vs Mobil 1

                            Originally posted by Ken 23434
                            I had a 2001 TT also. I always used the Mobil 1 Racing 4 (no T) from Autozone. I now have the 2006 Daytona 675. It calls for the same oil and now the Mobil 1 at Autozone says "4T". Not really sure what changed in it.
                            That's what I had also, an 01 that I bought new in 00. It was one of the sharpest looking bikes I ever owned. Beautiful caspian blue. Had the solar cover and the actual Triumph race can... It was also 1 of the loudest bikes I've ever heard with that pipe on it.
                            Back when I bought the bike I called Triumph in England and talked to the guys over there. They told me that their special 4T racing oil was Mobile 1 in their own bottle, for whatever that's worth.
                            just because you found it that way... doesn't mean it's supposed to be that way.

                            Part of diagnostics is spending time figuring out not only what the problem is, but also sorting through what it isn't.

                            The older the engine is, the chances of it having more than 1 problem goes up exponentially

                            Boating has always been a rich mans hobby. Buying a new boat gets cheaper every year, but the maintenance, the repairs, and the overall cost of ownership of a boat has never gotten any cheaper.

                            Comment



                            • #15
                              Re: Merc oil vs Mobil 1

                              Originally posted by Merc4ever View Post
                              Nothing can rust when covered in pure motor oil so I would have to say that pretty much all oil is anti corrosive.
                              And if you leave your engine sitting for 6 weeks in a moist marine environment, how long do you think certain parts are going to remain covered in oil?

                              The oil will quickly drain down to a very thin film indeed and then you have the parts at the top end (upper piston rings, cylinders, valve stems) where there was never much oil to begin with.

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