What octane should be running 2002 Ski Nautique Ford 351

[Houndawg100]

I’m sorry if this a repeat question in this forum. I can’t find a solid answer. I simple yes or no will be fine. 1. Should I run the 87 octane with 10 percent ethanol?

2. Or, should I run the 91 octane with no ethanol?

Signed,

Feeling dumb.

[JayG80]

"Use any good grade of automotive regular or premium gasoline with a minimum average octane rating of 89. An 87 average octane gasoline can be used if 89 octane is not available" quote from Manual page 8.10 that happened to be on my desk ;-)

[SatherG230]

If you want to avoid problems, use premium non-oxygenated fuel. 91 octane W/o ethanol. Fuel tends to sit in boats for a while. Ethanol absorbs moisture.
Premium stays fresher longer. That especially goes for small engines

[CHassmann]

I can't get fuel in my area that does not contain alcohol for my '02. If I were in your shoes, I would definitely choose the 91 octane without ethanol. I normally use 89 with sta-bil 360 Marine ethanol fuel treatment. I occasionally run higher octane or use fuel injector cleaner.

[SatherG230]

The Stabil Marine is good stuff. Stay away from the regular Stabol (red label). My local small engine guy says that is what keeps him in business! Seafoam is also a good additive. If you have to run ethanol, Star-tron enzyme treatment is also good to use.

[Nautiquehunter]

I must be the luckiest guy in the world. I have 5 boats all run on the cheapest 10% ethanol gas I can find. My 08 has over 1000 hours no problems yet?

[charlesml3]

I must be the luckiest guy in the world. I have 5 boats all run on the cheapest 10% ethanol gas I can find. My 08 has over 1000 hours no problems yet?

Ha! ha! Actually, you probably understand the realities around Octane and Ethanol...

It's amazing how in 2018 there is still so much myth around this.

-Charles

[Wake.BC]

Coming from an indmar guy I think these high octanes are crazy. Just do what your manual tells you and everything should be fine. Even my dealer was like yeah... just run 89


Sent from my iPhone using PLT Nautique

[charlesml3]

Coming from an indmar guy I think these high octanes are crazy. Just do what your manual tells you and everything should be fine. Even my dealer was like yeah... just run 89


Sent from my iPhone using PLT Nautique

There are a lot of myths around high-octane fuel such as:

- It'll last longer in a gas can or in your gas tank.

- It cleans your injectors

- It'll let the engine create more horsepower/torque (only true if the engine can tune itself for higher octane fuel).

- It'll make your engine last longer.

- 93 Octane fuel is better than 89 which is better than 87.

[Wake.BC]

There are a lot of myths around high-octane fuel such as:

- It'll last longer in a gas can or in your gas tank.

- It cleans your injectors

- It'll let the engine create more horsepower/torque (only true if the engine can tune itself for higher octane fuel).

- It'll make your engine last longer.

- 93 Octane fuel is better than 89 which is better than 87.

If I had the 575 I would definitely run 91 which it calls for but with the 440 89 is fine so that’s what I run....


Sent from my iPhone using PLT Nautique

[charlesml3]

If I had the 575 I would definitely run 91 which it calls for but with the 440 89 is fine so that’s what I run....


Sent from my iPhone using PLT Nautique

Yea. Higher compression engines (especially those with forced-induction) are what high-octane fuel is all about. The octane helps eliminate pre-ignition or "spark knock" as it's usually called. If you have to run a lower octane fuel in one of these engines, the ECU will detune the engine to eliminate the pre-ignition (with a corresponding reduction in HP/torque). On the other hand, running a high-octane fuel in an engine that doesn't need it won't do the opposite. In other words, it cannot "tune up" to take advantage of the higher octane.