What octane do you guys use for your boats?

Discussion in 'Bubba's Outboards' started by Nedo, Nov 17, 2006.

  1. Nedo

    Nedo New Member

    Messages:
    23
    State:
    Ontario
    I know that for vehicles, the higher the octane the better. Does the same apply for boats? Where I live we have 94 octane, would this be best to use? Does it give you a noticeable difference in performance? I have a 96 40hp evinrude if it makes a difference. Up to date I have been using 87 octane.
     
  2. cat tamer

    cat tamer New Member

    Messages:
    694
    State:
    MO
    I run at least 92 octane, it prevents alot of problems in the newer 4 strokes.
     

  3. Nedo

    Nedo New Member

    Messages:
    23
    State:
    Ontario
    I wonder if it reduces carbon build up like it does for cars
     
  4. cat tamer

    cat tamer New Member

    Messages:
    694
    State:
    MO
    it keeps from building up a residue on the plugs.not so much carbon but a clear residue that is not noticable to see. supposably a additive that is the lower octane gas.
     
  5. MattShannon

    MattShannon New Member

    Messages:
    829
    State:
    WV
    87 octatane. I have a 4cyl Merc I/O.
     
  6. SeedTick

    SeedTick New Member

    Messages:
    1,414
    State:
    Conway Arkansas
    I always just run regular in mine. I currently have a 25 hp Nissan and the operator's manual says to use gasoline above 86 octane. It seems like I recall somebody saying to just run the 87 octane unless otherwise specified. Maybe Bobpaul and Bubba will chime in here.

    st
     
  7. blackwaterkatz

    blackwaterkatz Active Member

    Messages:
    3,659
    State:
    Andrews, SC
    The owner manuals for my boat motors and my vehicles specify 87 octane fuel and they all run just fine with them so that's what I use. I do add a fuel stabilizer to my outboard gasoline, as well as an occasional can of sea foam.
     
  8. olefin

    olefin New Member

    Messages:
    3,908
    State:
    Texas
    Myself... same as with my vehicles... I go by the recommendation in my Owners Manual. My Yamaha and Merc calls for 87 octane and thats what I use. I always add Sta-Bil for winter storage.
     
  9. Shortarms

    Shortarms New Member

    Messages:
    48
    State:
    Illinois
    As I understand it, octane is a rating of a fuel's ability to resist volatile explosion. A fuel with a higher octane rating burns in controlled layers and a lower rated fuel is more volatile and tends to explode or violently combust more. An under powered car may have a tendency to spark knock under a heavy load and can be corrected by adding a higher octane fuel. I don't believe octane rating plays a role in the cleanliness of the fuel or the amount of carbon it produces. I've always been told that you can run the lowest octane rated fuel that doesn't cause a problem, like spark knock, unless otherwise specified. I have no idea how that plays into boats or 2 strokes.
     
  10. crome

    crome New Member

    Messages:
    328
    State:
    ilm,nc
    my 2005 yamaha 4 stroke calls for 87 octane,and runs good with it.
     
  11. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Always use what your owners manuel or repair manuel says to use. That 96--40 h/p will operate well on 87 octane and it will burn higher but with no added benfits. Add some stabil or seafoam I use seafoam because it seems to clean the carbon a little better.

    I can't say for a 2 stroke made after 2000 because I haven't took the time to read up on it but I will do this.
     
  12. Mark J

    Mark J New Member

    Messages:
    9,407
    State:
    Four Oaks, NC
    Yes, like Bubba says it requires the owner's manual.
    I have a 87 Mariner that the manual says 93 octane, 94 octane if available.
     
  13. metalman

    metalman Well-Known Member

    Messages:
    3,457
    State:
    IN
    Name:
    Winston
    Nedo,
    It doesn't apply to boats or cars. Higher octane fuel may prevent knocking in some cases but using it just for the sake of it gives you nothing and is a waste of money.

    Nedo,
    Higher octane fuels do not reduce carbon buildup...W
     
  14. cat tamer

    cat tamer New Member

    Messages:
    694
    State:
    MO
     
  15. metalman

    metalman Well-Known Member

    Messages:
    3,457
    State:
    IN
    Name:
    Winston
     
  16. trnsmsn

    trnsmsn New Member

    Messages:
    1,214
    State:
    Missouri Originally Now I
    I've used the 93 & 87 Octane fuels and can't tell a difference, so I've stayed with the 87 octane. The motor is a 2000-4 Stroke, 70hp Suzuki.

    I couldn't find any recommendations in my Clymer's repair manual:roll_eyes: . I do use Lucas Fuel stabilzer in each tank.....So far....So good
     
  17. cat tamer

    cat tamer New Member

    Messages:
    694
    State:
    MO
    wb,
    youre right using higher octane for the heck of it is a waste of money and what I said was to use what the manual recomends and you won't be paying for unnecessary repairs.
     
  18. gilmafam

    gilmafam Well-Known Member

    Messages:
    5,466
    State:
    California
    My 2003 Honda 4/s calls for the 87 octane.... I have a 40 gal tank and fish as much as I can.. Lots of trolling (for other fish) and as I check out the plugs @ 400 hrs, I noticed 1 plug somewhat different than the others. I had the boys do a valve adjustment( not that It was running bad)....wanted to keep ahead of things..... I have a water separator, and use Sta/Bil addative to boot.
     
  19. bigredsbbq

    bigredsbbq New Member

    Messages:
    293
    State:
    Illinois
    kick me in the head here if I'm wrong but my owners manual says use 87 what I was told is the higher octane fuels should not be used in my motor it's a 81 johnson 2 stroke something about the higher octane fuels burn hotter and more complete witch is not good for the older 2 stroke motors
     
  20. trnsmsn

    trnsmsn New Member

    Messages:
    1,214
    State:
    Missouri Originally Now I
    My 2003 Honda ATV says, "Do not use 93 Octane gas". I believe that there are more additives in the "premium" grade gas that while in use may be/are beneficial but in applications where sedentary usuage is common, they deteriorate & then become harmful, JMHO:roll_eyes: