Merc 4S 250 XS octane?

[MakingWaves]

I have one dealer telling me to use midrange octane, another is telling me premium octane. Help?

[MichaelJ3]

Read your owners manual and do what it says in there.

Oh, and check the forum announcements and post the requested information..

[FD209]

87

[EuropeanAM]

If you would, please take a moment to review the Announcements at the Top of the Forum, and be sure to provide the Required Info when posting. Thanks!

[MakingWaves]

Thx guys

[BigBucketMouth33]

I always run mid grade at the least and non ethanol as much as possible. Haven't had any issues..

[Hookedup2]

I have only ran 87 in my 2 stroke and never a problem for 300 hours replaced with a 4 stroke and 75 hours no problems.

[EuropeanAM]

....fine.

The word used in literature is acceptable (not good, better, best, fine, or recommended).

[Steve Albertson]

The word used in literature is acceptable (not good, better, best, fine, or recommended).

So run 87 or 89?

[bassmasterffej]

Lol

[MakingWaves]

I've filled the boat up twice since starting the post. Put 91 octane both times..

[tuffnugly81]

Only non ethanol fuel I have around here is 91. So 91 it will be....

[mikesxpress]

Running my 4.6L since last July. I experimented with non E fuel and standard 87 E fuel multiple times. I wanted to believe the 91 octane would run better but it really isn't noticeable in performance or fuel mileage. Sticking with the 87 E fuel.

[EuropeanAM]

Folks- 87 octane is the recommended fuel.

Fuel Selection:

Make your fuel selections based on the following criteria, IN THE FOLLOWING ORDER:

-High Traffic, Top-Tier (Name Brand) Fuel
-Appropriate Octane Rating (see above info)
-Lowest possible ethanol content (NEVER to exceed 10%).
-While it may be preferable to utilize a fuel that contains lower (or no) ethanol, use of fuels that are higher octane than is required can result in decreased performance, decreased fuel economy, and potential for carbon buildup. Higher octane fuels burn SLOWER and COOLER. Essentially... that "better" fuel may be costing you coming, and going.

[MakingWaves]

Folks- 87 octane is the recommended fuel.

Fuel Selection:

Make your fuel selections based on the following criteria, IN THE FOLLOWING ORDER:

-High Traffic, Top-Tier (Name Brand) Fuel
-Appropriate Octane Rating (see above info)
-Lowest possible ethanol content (NEVER to exceed 10%).
-While it may be preferable to utilize a fuel that contains lower (or no) ethanol, use of fuels that are higher octane than is required can result in decreased performance, decreased fuel economy, and potential for carbon buildup. Higher octane fuels burn SLOWER and COOLER. Essentially... that "better" fuel may be costing you coming, and going.

Great info. Guess I'll go back to the 87 (I can still find one station with no ethanol). Thx again