Manual says use premium?

[ab1]

93 150 GLETR

I've seen a bunch of posts that say only to use regular, 87 octane in our J/E outboards. Many of these have been from the go-to guys on this forum.

My OEM service manual states that 87 is the min. But...it has a 'note' that states 'the use of premium grade fuel is specifically encouraged' because it contains detergent and dispersant to reduce deposits, carbon, etc....It does not specify what octane number they consider premium.

So what's the scoop?..I know I'm fine with 87 as a minimum, I decarb once a year, and mix seafoam in every few tanks. Should I go to a higher octane, 89 or 93? I don't want to cause any issues as some have suggested might come with higher octane (preignition?), but I also tend to trust the manual. Is there better performance to be had above 87 with this particular motor?

 

[jay_merrill]

Re: Manual says use premium?

You would not get preignition by going to a higher octane. In fact, you should less likely to have this, than with a lower octane fuel. I don't know much about your motor, specifically, but if you have had it for some time and it performs well on 87, I don't see why you should go to 93. I suppose that folks that want to get every last bit of performanace out of an engine would, but for everyday use, the extra fuel cost might not be worth it.



???

 

[JB]

Re: Manual says use premium?

What was in "premium" fuel in 1993 is not very close to what is in it in 2010.

By far not the only example of obsolete recommendations.

Use 87.