What octane

[Tleazenby]

what octane should be run in 1999 yamaha 115.<br />The engine runs great except at idle it want's to run rich if I run 86/87 octane would that help rather than the higher octane of 90. Any thoughts would be great.

 

[12Footer]

Re: What octane

Stick with what Yamaha recommends. If they say 87,stick to it.<br />Octane is misunderstood by many people. <br />They think the higher the octane, the more explosive the air/fuel mix, when in actuality, its reverse. The higher the octane number, the LESS explosive it is.<br />If you hear any "pinging" goin-on while underway, stop imediately,and add octane booster until the tank is empty. Then go up on the octane number.<br />Also, higher octane fuels,by burning slower<br />and cooler, to carbon-up the innards,and foul plugs.Stear clear of fuels with alchohol in it,as it devours the fuel pump diaphram,and all other rubber parts in the fuel deliviery system.

 

[JB]

Re: What octane

Howdy lazenby. You didn't say, but I assume your Yammy 115 is a two stroke, as the F115 just came out in 2000.<br /><br />If it is a 2 stroke, amen to 12footer's comments. Go with Yamaha's recommendation. I don't recall ever seeing a non-racing 2 stroke of any kind that needed premium fuel. Lots of guys waste lots of money using premium and then decarbonizing.<br /><br />If I am wrong, and your motor is a 4 stroke, it may need premium. If so, Yamaha will say so in the manual.<br />Good luck.<br />JB

 

[Tleazenby]

Re: What octane

Thanks for the info I think this answers some questions I been having. I been running 91 octane and I think this is why it's not burning the fuel/oil mixture very well while idling. One last question should I use some type of additive to clean it out.?

 

[Tleazenby]

Re: What octane

To cormwell yes you are correct it is a 2 cycle what should I use to clean it out.

 

[JB]

Re: What octane

Yo, leazenby. Use what your Yammy dealer recommends, unless the manual calls for a specific product.<br /><br />Good luck.<br />JB

 

[12Footer]

Re: What octane

Lotsa folks use a fogging cleaner like Valvtect "Marine Motor Decarb" as a first step in winterising. I live in Florida,but still fog mine 2times a year,or after 80 hours.<br />But you axed about additives. I use Seafoam, but have problems with it when used at the dosages recommended on the bottle. It tends to knock the octane into the ozone on my Force,and it doesn't like to idle. I use a bit more than half the recommended dose.<br />But that's me with an old motor.<br /><br /><br />------------------<br />Time to change my tagline

 

[Tleazenby]

Re: What octane

Thanks for the help guys I ran a half tank of gas through her today with ring free from yamaha. At first she was hesitant at 5,000 rpm after about 1o mins she quit being hesitant an and was running soomth at 5300 rpm and idling great.<br /><br />One last question if I may what should the timing be set at on this 115 1999 tlry oil injected yamaha.?

 

[12Footer]

Re: What octane

Sorry.<br /> I don't have the book on your motor,so <br />I don't have the timing scpecs.<br />But post a new msg,and surely, someone will.<br />They just probably not see your question in this thread.