yamaha 8hp fuel mix

madxbri

Seaman Apprentice
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Jul 30, 2003
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ok all my outboard (yamaha 8hp)runs great now but i have bn told by many people diffrent reasons for diffrent mixes for the pre mix <br />i have bn told to mix at 50;1 and 100;1 <br />100;1 i have bn told will make it last longer as it is an old motor but it seams to be smokey to me with this mix what would you alll recomend and why if possible i dont want to blow my motor and only just got it so all info would be great <br />thanks again <br />Brian
 

JB

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Mar 25, 2001
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45,907
Re: yamaha 8hp fuel mix

Howdy, MXB<br /><br />Wrong. 50:1 will make it last longer. That is what I recommend you use.<br /><br />Many of the engines recommended for 100:1 back in the 80s and early 90s exhibited internal corrosion from too little oil coating very corrosion-vulnerable parts. A few others tried at 100:1 simply blew up.<br /><br />Unless you want to use an expen$ive $ynthetic like Am$oil, use 50:1.<br /><br />Good luck. :)
 

plot4

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Mar 30, 2004
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Re: yamaha 8hp fuel mix

Guys,<br /> Yamaha doesn't just pick a number for the <br />fuel/oil ratio. When it says 100to1 thats what they mean.By the way they are not giving you <br />false info so you will blow up your engine and<br />have to buy a new one.Just because someone<br />mixes it at 50to1 and has not blown up their <br />motor up dosen't make it wright.
 

madxbri

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Jul 30, 2003
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Re: yamaha 8hp fuel mix

again 2 opinions anyone know what is meant to be used in this outboard still non the wiser <br />but thanks again i was running 100/1 on my johnson 4 hp and no problem but not sure about this yamaha 8 hp as much info on this would be great looks like 50/1 i should be using but still need an opinion on this
 

plot4

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Mar 30, 2004
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Re: yamaha 8hp fuel mix

The product infomation guide for YAMAHA outboards<br />1996 and 2003 state for 8 hp 100/1
 

madxbri

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Jul 30, 2003
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Re: yamaha 8hp fuel mix

my outboard is in the 80's or around there <br />so not to sure thats why i was needing to know the mix as it is so old but runs great and i would rather it stay that way <br />thanks again for info
 

madxbri

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Jul 30, 2003
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Re: yamaha 8hp fuel mix

no one else have an opinion on this fuel mix amount ? <br />still a bit mixed up myself with this 50/1 or 100/1 what am i best mixing this to as you will read above i got 2 diffrent answers anyone have the same old yamaha 8 hp that can advise on this matter will it run better on 50/1 or 100/1 will one not burn less eficiant with there being more oil in the fuel ect ect <br />thanks again <br />Brian
 

rickdb1boat

Supreme Mariner
Joined
Jan 23, 2002
Messages
11,195
Re: yamaha 8hp fuel mix

Agree with JB. 50;1 is better. Call your dealer and ask him... OMC also used to recommend 100:1, but then realized that was not enough lube to protect the cylinder walls and such during storage, not to mention when running..
 

Luna Sea

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May 20, 2002
Messages
1,070
Re: yamaha 8hp fuel mix

Compromise, 75:1.......... :rolleyes: <br /><br />I think you should list the model/serial # so someone can look it up in a manual for that year.
 

plot4

Cadet
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Mar 30, 2004
Messages
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Re: yamaha 8hp fuel mix

Yamaha 8 hp have always had a 100/1 ratio on the fuel oil mix.
 

rickdb1boat

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Jan 23, 2002
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11,195
Re: yamaha 8hp fuel mix

What makes this motor any different from any other. Is this some kind of "special" motor that will tolerate a 100:1 mix, when almost every other one requires a 50:1 mix? I'd really like to know what makes this motor exempt from a 50:1 mix. And just saying because they "Recommend" it is not what I'm after....
 

madxbri

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Messages
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Re: yamaha 8hp fuel mix

wow i didint know that the question would stirr up so many ideas i would think personaly that although a little smokey that 50/1 would protect the engine better than 100/1 so i will stick with the 50/1 unless anyone has info on this causing damage to my outboard <br />i could get the engine number ect if need be but as its old i would have thought the more oil the better protection that is withought going over the top with the mix most people will agre with 50/1 mix <br />thanks for the info nice one
 

andrewkafp

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Mar 15, 2003
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1,668
Re: yamaha 8hp fuel mix

If you know your model and year.. This might help you.<br /><br /> http://archive.bibalex.org/web/20010801165541/goa-northcoastoil.com/tips/obmixing.html <br /><br />YAMAHA <br />2-Stroke Engines SHIPMATE Outboard TC-W3 <br />3.5, 5, 7.5 hp 1968-70 20:1 <br />Premix Engines <br />C40 (2cyl) 1997-99 100:1 <br />C40 (3-cyl),C55, C75, C80, C85, C90, C115, C150, E48, E60, E75 1989-99 50:1 <br />All Others 1984-99 100:1<br /><br />It could well be a 100:1 motor.. My 1986 Suzuki 6hp is. Just make DEAD sure first. 100:1 will most likey kill a motor designed for 50:1<br /><br />Did you know that Yamaha pioneered 100:1 fuel:eek:il ratio in 1984. ??
 

199675hpforce

Petty Officer 1st Class
Joined
Feb 27, 2004
Messages
299
Re: yamaha 8hp fuel mix

i am running a gallons worth more oil in mine for every 5 gallons of gas so thats 20percent more oil. My force says 50-1 so im like 40 to 1 mine old crapper runs better.
 
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