Need octane (87 vs 89) education...

[VELOCITOY]

...I run the gas docks at a marina in N.H....We are a MAJOR Mercruiser dealer & sell LOTS of gas...My boss is considering changing from 89 octane to 87 octane...What are your thoughts on this???...THANX in advance...you guys have steered me in the right direction more than once...:D ...

[Brad Zastrow]

Why? Gas at a marina is normally high priced anyway, so what favor is he doing to anyone by selling cheaper gas? Many outboards require 89 or higher. I think most marinas here only sell premium.

[WATERWINGS]

Mabey they want to charge the same price, but buy cheaper gas?

[VELOCITOY]

FYI...The money IS NOT the issue...I am asking about the octane/performance/motor "damage" issues & motor requirements...THANX...

[SKATER241]

ALMOST ALL THE MARINAS AROUND HERE SELL PREMIUM 92 OCTANE.THIS IS A MINIMUM REQUIREMENT FOR THE HI PERF MOTORS.IF ANYTHING I WOULD SUGGEST TO HIM HE UP THE OCTANE NOT LOWER IT.HE WOULD PROBABLY SELL MORE GAS THAT WAY.

[optimax135]

89 octane is right down the middle of the road for marine products which I advise my customers to use. If you drop the octane to 87 you may run into the situation of octane loss to your customers who fill up and let their boat sit for weeks. How much octane is lost in fuel that sits for three or four weeks? It could be an issue. As far as the 92 octane, I frown on that because the oil companies add more alcohol to it to bring the octane up. Alcohol draws moisture which in a boat isn't a good thing. I'd stick to the 89..................

[VELOCITOY]

Thanx OPTIMAX...That was the kind of feed- back I was looking for...Feel free to chime in boyz...

[Travis Fulton]

i thought alchoal helps counter act the moisture???

[ncst8er]

Probably more correctly, alcohol absorbs water (which is one reason it's used to remove water from lab equipment). If you already have water it will absorb it and help carry it through the system & out of the system (most of the water treatment additives are an alcohol). The potential downside is that if you don't have water in the sytem, it MAY attract it (but usually only the amount it can absorb). Probably a bigger risk (especially for older motors) is that some items (certain rubbers in particular), may be attacked by it if the concentration is high enough; that's one reason why gasohol used to be limited to 10% (don't know if it still is). Newer motors have probably addressed this in their choice of materials. Of course the other problem with the older motors is they were designed for higher octane especially the Merc inlines and may detonate with lower octane fuels (damned if you do, damned if you don't). Either way, I agree that 87 octane is the wrong move (especially for 2 cycle engines).

[VELOCITOY]

THANX BOYZ...FYI...I am looking at the MERCRUISER fuel recommendations & with the exception of the supercharged motors MERC recommends 87 octane for most everything else (esp. the early EFI motors...more octane in these will cause a CODE 43 in the ECM unit...ECM "thinks" the knock sensor is not working...)...this isn't true of the latest stuff tho...higher octane CAN be used but isn't needed...SOOOOOOO...The dilemma remains...Do we go to 87???...or???...stick with the 89 octane???...OPTIMAX135...You make an EXCELLENT point...Any other suggestions boyz???...:confused: ...

[VELOCITOY]

ttt...feed me fellas...:D ....thanx

[VELOCITOY]

ttt...any other thoughts boyz...???...THANX...:confused: