Oil mix

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  • The Boat House


    Replies: 4549
    Topics: 111
    #248137

    The section of a bearing that is under pressure
    as a motor runs has the thinnest film of oil.
    There is only room for so much oil there no
    matter how much you mix in to fuel. Once you
    have enough to prevent contact, there is no
    benefit to adding more. Then there is friction.
    The slicker the oil the less wear. You see it’s
    the friction of the oil as the components rotate
    that wears away the metal. Just as water does
    running over a stone. It’s the same for the rings.
    For me it’s the quality that will reduce wear
    resulting in longer engine life. Others obviously
    see it differently.


    rudderless


    Replies: 159
    Topics: 5
    #248138

    …feed that journal with premix…50/1 verses 16/1 on a plain bearing….not my motor…roller elements 50/1 is fine. With a high silicon piston skirt 50/1 is okay when things are perfect. Early pistons were soft and need 16/1.

    I understand the gas flashes off leaving the oil film. 50/1 is not enough oil for a non-pressure fed plain bearing. 50/1 was a boardroom decision for sales. The newer crowd sees an oil cloud they assume the motor is worn out like a 4 stroke.

    The very first week of getting my 4 year in mechanical the prof says any product that lasts too long is a product failure…and products are designed to make investors money but that’s another issue..

    • This reply was modified 2 years, 5 months ago by rudderless.
    • This reply was modified 2 years, 5 months ago by rudderless.
    • This reply was modified 2 years, 5 months ago by rudderless.
    • This reply was modified 2 years, 5 months ago by rudderless.
    • This reply was modified 2 years, 5 months ago by rudderless.

    JOHN HOLBIK


    Replies: 162
    Topics: 2
    #248144

    When OMC switiched to 50 to 1 all the motors had fixed high speed jet which prevented operators from running them too lean.


    rudderless


    Replies: 159
    Topics: 5
    #248162

    …and keeps operators from running slightly rich for safety. Every fixed jetted carb motor I have received I go one hotter plug and jet to that. The folx on the chainsaw forums understand this. Manufactures have no incentive to make their products live much past warranty period. By running short on oil and slightly lean this is accomplished.

    The only 4 stroke outboard I have owned from new was jetted too lean for optimum operation also. Most carbed 4 strokes of today are jetted slightly lean …especially the low speed jet.

    • This reply was modified 2 years, 5 months ago by rudderless.

    fleetwin

    US Member - 2 Years
    Replies: 4737
    Topics: 46
    #248255

    I stand by my opinion expressed before, this OMC recommendation is dangerous when it comes to CD/AD series engines with plain bearings. 16:1 is what should still be used. The beauty part of these engines is that they smoke very little, even at 16:1 when in good shape and properly tuned…


    Mumbles


    Replies: 5764
    Topics: 298
    #248267

    Here’s a ’58 Johnson CD which I just finished servicing. It’s running on a 16:1 mix using Canadian Tire dino oil and shows no smoke at idle and just a bit when revved up some.. This wouldn’t even be noticeable if it was on a boat out on a lake.

    https://youtu.be/Jd5aXcDIJWA


    fleetwin

    US Member - 2 Years
    Replies: 4737
    Topics: 46
    #248281

    Here’s a ’58 Johnson CD which I just finished servicing. It’s running on a 16:1 mix using Canadian Tire dino oil and shows no smoke at idle and just a bit when revved up some.. This wouldn’t even be noticeable if it was on a boat out on a lake.

    https://youtu.be/Jd5aXcDIJWA

    What a beautiful engine, thanks for the testament to the old engines….


    rudderless


    Replies: 159
    Topics: 5
    #248297

    Anyone remember the 100/1 recommended mix some years ago? how’d that go…


    Monte NZ

    International Member - 2 Years
    Replies: 304
    Topics: 89
    #248336

    I remember seeing a can back about 1963……..can’t remember the brand. It was in a small sealed can, similar to a baked bean can, but smaller. I think it came from Singapore and if I remember correctly, it had a warning on it that it wasn’t good for your health and to be careful using it.

    It was a bit of an eye opener to us young guys who were used to using 24 to one oil ratios

    Monte NZ


    fleetwin

    US Member - 2 Years
    Replies: 4737
    Topics: 46
    #248339

    Anyone remember the 100/1 recommended mix some years ago? how’d that go…

    Great point indeed…. This is what happens when the marketing department has way too much control….

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