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  1. #1
    Cadet
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    Default 40:1 vs. 50:1 oil mix??

    This actually applies to all outboards, but I'm running an older Johnson, so I'll ask it here. I know the recommended oil mix for a 1971 johnson 50 is 50:1, but I'm paranoid about a motor of this "vintage" burning up on me. Would running a 40:1 mix be a good "safety margin" or am I just wasting oil, or perhaps even doing harm to the engine by considering this?? Logic tells me that a little extra oil couldn't hurt, and might even keep some extra lubrication going, but I thought I'd get opinions from some people here on the board. Overall, the motor is in good shape, I broke it down and did a re-build during the past week (all new gaskets, new coils, new starter, rebuild the carbs etc.) and thought that for at least a break in period, some extra oil might be good for it.
    let me know what you guys think
    Thanks,
    Andrew

  2. #2
    Admiral CATransplant's Avatar
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    Default Re: 40:1 vs. 50:1 oil mix??

    Actually, I run 40:1 in older outboards, just for the safety margin. It may not be necessary, but I don't notice extra smoke and it doesn't appear to hurt the running characteristics.

    Of course, an Amsoil person will be on here shortly to tell you to run 100:1 with Amsoil.

  3. #3
    Supreme Mariner
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    Default Re: 40:1 vs. 50:1 oil mix??

    By rebuild do you mean pistons and rings? Otherwise, extra oil is completely unnecessary. But it won't hurt anything either, except maybe the environment depending on whether or not you hug trees.

    Old engines destruct mostly from water getting in where it doesn't belong. A little extra oil might help keep it from rusting from that, but very little. If it's getting water in it, it will blow anyway, no matter how much oil you slop in.

  4. #4
    Supreme Mariner
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    Default Re: 40:1 vs. 50:1 oil mix??

    I'm sure there are lots out there running running motors older than yours at 50:1.I know the official word is you can run 50:1 back to 1960 on larger OMC
    motors. The old Fat 4s are 58 and run 50:1.
    It's not going to do any damage either way.If you run trolling speed a lot
    40:1 may be a bit much.If you work it hard 40:1 may be a good idea.

  5. #5
    Admiral LubeDude's Avatar
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    Default Re: 40:1 vs. 50:1 oil mix??

    Quote Originally Posted by CATransplant View Post

    Of course, an Amsoil person will be on here shortly to tell you to run 100:1 with Amsoil.
    Now who do we know around here that would tell anyone that?

    I actually would recommend the new Saber 100:1 ran at around 80:1, That`s one bottle to five gallons instead of six if I were to recommend useing Amsoil! Which I`m not, but I could, I have before, I have used it myself and it`s awesome, It`s your choice.

  6. #6
    Moderator JB's Avatar
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    Default Re: 40:1 vs. 50:1 oil mix??

    Any mix richer than 50:1 with TC-W3 oil is a waste of oil on a '71 JohnnyRude 50.

    I don't understand how so many people get so much smarter than the people who designed and built Outboards.

  7. #7
    Captain
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    Default Re: 40:1 vs. 50:1 oil mix??

    Well,why do you want to run a thirty something motor on less oil than they said back in 1971? Yes today's oils are lots better.But you still have a motor that is old.It has alot of wear on it,so I would use the regular Johnson/Evinrude Oil
    that you've been using.

    DHP

  8. #8
    Petty Officer 2nd Class
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    Default Re: 40:1 vs. 50:1 oil mix??

    I ran 40:1 in my 6 hp Johnson for many years because the motor was always exposed to salt water environment and the richer mix makes everything kind of oily. I recently returned to 50:1 because of the smoke which has become embarasing(sp) in my harbor. If you use 40:1, it's a good Idea to adjust the carb needles for this fuel; it makes a difference.

  9. #9
    Cadet
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    Default Re: 40:1 vs. 50:1 oil mix??

    Quote Originally Posted by DHPMARINE View Post
    Well,why do you want to run a thirty something motor on less oil than they said back in 1971? Yes today's oils are lots better.But you still have a motor that is old.It has alot of wear on it,so I would use the regular Johnson/Evinrude Oil
    that you've been using.

    DHP
    Actually, 40:1 is more oil than 50:1 ....
    But, I digress. When I said rebuild, it included pistons and rings in addition to all the electrical & gaskets. I'm running out a tank of 40:1 and I'll move back to 50:1 on the next fill up, just to see if there's a performance gain. If not, I'll adjust back to the 40:1, if for nothing else than it makes me feel better to allow "a little insurance"
    Thanks for all the replys
    A.

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