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  1. #1
    Join Date
    Jul 2017
    Posts
    8

    Default 1990 Conbrio Oil?

    My first stern drive, beautiful boat with 650hrs with a PCM 351 Windsor. Looking to do an oil change after my next outing on the water. Any suggestions on what to run for engine oil? I'm located in AB Canada. Thanks!

  2. #2
    Join Date
    Aug 2010
    Location
    Oyama, B C , Canada
    Posts
    650

    Default

    Manual says 30 weight oil for your average outside temp range.
    See photo below taken from manual.
    I have 89 conbrio with 351w and run 30 weight semi synthetic.
    Enjoy you new purchase.
    Great boat!

    IMG_3132.jpgIMG_3132.jpg

  3. #3
    Join Date
    Jul 2007
    Location
    Flowery Branch Georgia
    Posts
    2,742

    Default

    For the past 30 years I have been running Mobil 1 15w50 in all my boats . 15 w 50 is the only weight recommended by Mobil for both roller and flat lifter engines.

  4. #4
    Join Date
    Jul 2017
    Posts
    8

    Default

    Thanks for the info gents. Michael, is the Mobil 1 15w50 you run in your boats a full synthetic or conventional? I tried to google Mobil 1 15w50 and could only find a full synthetic. If that's the case, I'm a bit leary as the original owner only ran conventional oil. With 650 hrs on the engine, I'm a bit reluctant to swap to a full syntheic at this point..?

  5. #5
    Join Date
    Jul 2017
    Posts
    8

    Default

    Quote Originally Posted by crystal waters View Post
    Manual says 30 weight oil for your average outside temp range.
    See photo below taken from manual.
    I have 89 conbrio with 351w and run 30 weight semi synthetic.
    Enjoy you new purchase.
    Great boat!

    IMG_3132.jpgIMG_3132.jpg
    So....are you running straight 30 weight or a 5w30/10w30 synthetic blend?? sorry for the dumb questions...

  6. #6

    Default

    I'm not sure if your motor is still a flat tappet or not but it wouldn't hurt to add some ZDDP or zinc additive just to be safe. Over the past decade or so they have removed a lot of the zinc and other engine protecting additives because they have a tendency to clog catalytic converters . Since you don't have to worry about cats in an older boat I would suggest an additive like STP's ZDDP as cheap insurance. I personally run Lucas 15w-40 Hot Rod blend with zinc.
    Happy Boating!


    Sent from my iPhone using Tapatalk
    1986 Supra Sunsport Skier with 351W and swivel spotters seat

  7. #7
    Join Date
    Sep 2015
    Location
    Pendleton IN
    Posts
    100

    Default

    I used Valvoline VR1 that has a zinc additive as well. I agree with the zinc comments above. Seems Mobile 1, Royal purple, Rotella, and VR1 all have pretty high Zinc

  8. #8
    Join Date
    Dec 2016
    Location
    Louisville, KY
    Posts
    137

    Default

    Vr1 for me. But Michael Hunter is guru so either or. This is age old debate.


    Sent from my iPhone using Tapatalk
    '92 Comp ts6m - 5.8 PCM Pro Boss Carb
    '02 Launch SS - 5.7 Indmar Assualt TBI

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