Fuel oil mixture

Discussion in 'Outboard Maintenance' started by UFgatorbait, Aug 24, 2013.

  1. UFgatorbait

    UFgatorbait I Love microskiff.com!

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    I have a 2005 broken in yamaha 8hp 2 stroke with a 3 gallon fuel tank. How much oil and stabil should u mix with the fuel. Thank u so much I don't have the manual to look for myself.
     
  2. Creek Runner

    Creek Runner Well-Known Member

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    Oil/gas is 100:1 or 3.84oz per 3 gallons of gas. Read the back of the Stabil to see what the mixture it recommends

    Creek
     

  3. UFgatorbait

    UFgatorbait I Love microskiff.com!

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    I had someone tell me 8oz of oil per 3 gallons can someone please clarify for me.
     
  4. AfterHours2

    AfterHours2 Stripper in my own Mind!

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    My 25 Yami is 100:1 also but my mechanic recommends going a little heavier. 100:1 doesn't leave much room for error so I'm at 70-75:1 just to be safe.. Make sure to use the Yamalube also if you haven't already...
     
  5. UFgatorbait

    UFgatorbait I Love microskiff.com!

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    so what would 70 percent oil mixture be in a 3 gallon tank. how many ounces of oil.
     
  6. AfterHours2

    AfterHours2 Stripper in my own Mind!

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    Best bet is to buy a mixture container with the ratios listed for you but I would go 5-6 oz just to be safe..
     
  7. Creek Runner

    Creek Runner Well-Known Member

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    I'm a certified Yamaha technician, 100:1 is what I recommend and the engineers who designed the thing. 3.84 oz /3gallons of gas.

    Btw you can download an owners manual on Yamahas website for free.

    You can mix it a little heavy if you want like af2 said but I wouldn't go more than 4.5oz/3gallons.
     
  8. AfterHours2

    AfterHours2 Stripper in my own Mind!

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    Quick question for ya Creek, why is it that my mechanic cringed when I told him I was originally running the 100:1 like posted on the motor. He made it sound like it was creating a very lean condition and told me to change it immediately. Sorry to derail..
     
  9. Creek Runner

    Creek Runner Well-Known Member

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    Your engine is a little different it's a 25hp, it won't hurt it to run 75:1, even though Yamaha calls for 100:1. The op motor is an 8hp and just doesn't have the displacement, compression ratio, etc etc to run the extra oil.

    Think of it like this, a ford 5.0 liter V8 will call for 10w30 motor oil. Where as a Honda 4cyc, is going to call for 5w20.

    The smaller engines just don't need and it really isn't good for them to have the extra oil, when its not called for.

    But I also think your engine would perform a little better at 100:1 probably get an extra 100 RPM's or so, since you run the extra oil make sure you run ring free through it.

    Not sure why your mechanic made a big deal about it though, unless he is old school, all the old school guys think 50:1 is the only thing that is right. My dad is like that, great technician but you know what they say hard to teach an old dog new tricks.
     
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