What fuel Octane for '98 with 325 Monsoon?

[mtnbkr738]

Hi all,

there is a new Kwik trip near our lake. they sell 87 and the cheaper 88 E15  and a 93 octane.

Ive always run midgrade 89 octane.

can i run the cheaper 88 or upgrade to the 93?? or find different gas station.?

Any help appreciated thx!

dan

[oldjeep]

Should run fine on 87.  Do not run e15 in a motor that was not designed for it. 

[hawaiianstyln]

I believe in your manual it should state these engines perform off 87 (monsoon specifically).  No need to waste money on higher octane you will not notice or feel increased performance by doing so.  I just run a full can of SeaFoam through mine about every 6 tanks

 

[mtnbkr738]

On 4/15/2019 at 3:00 PM, hawaiianstyln said:

I believe in your manual it should state these engines perform off 87 (monsoon specifically).  No need to waste money on higher octane you will not notice or feel increased performance by doing so.  I just run a full can of SeaFoam through mine about every 6 tanks

 

So my manual says 89... ive always been running 89... but............ if it saved money with no harm then im happy to switch to 87. But why the sea foam every 6 tanks????

Edited April 17, 2019 by mtnbkr738

[MadMan]

Yep, don't put e15 in it.  If it were me, I'd run 89 minimum.  If that was the most convenient station, I'd mix half 87 and half 93. 

[jrvs23]

If you haven't changed out your fuel lines I'd go with the premium as it doesnt contain ethanol. The ethonal will dry out your fuel lines.

[oldjeep]

5 minutes ago, jrvs23 said:

If you haven't changed out your fuel lines I'd go with the premium as it doesnt contain ethanol. The ethonal will dry out your fuel lines.

Meh.  We have had E10 in pretty much everything since the late 80's.  never once seen an issue running it other than clogged fuel filters from it cleaning all the crap out of the fuel system.

Besides, in that picture of the pump - all 3 of his options have ethanol.  The 87 and 93 are E10 and the 88 is E15

Edited April 17, 2019 by oldjeep

[UWSkier]

Think 98 Monsoon was same as the '01.  We have two '01 Monsoons in my family.  Both are perfectly happy on 87 E10.

[Woodski]

Compression ratio on these engines is only 9.4:1, timing advance is max at 34 DBTC and water temp is 'cold' at 140 / 160 deg F.   Nothing that would require more than 87 octane at sea level using pump gas (up to 10% ethanol).   As noted, don't go with E85.  I believe and certainly follow the owners manual rather than my comments, they indicate 89 octane fuel mainly due to the potential of prolonged storage and time gaps between running, the potential of water absorption as our boats sit on lifts, etc.  So really some insurance against fuel deterioration potential.