87 Octane VS 89 Octane

[KLIEBERT]

My 2006 200 Opti has been drinking 89 octane fuel since day one, along with Quick clean & Fuel stablizer per recomandation from the Merc tech at the dealer where I purchased the engine. Now I hear that 87 is the correct fuel, should I change to 87 ? Did I damaged my engine ? 81 hrs on engine......Kliebert

[jovous21]

I don't think so I run 89 in everything that I own. I've heard that it burns at a lower temperature which helps the life of your motors. I may be wrong but thats what I do.

[EuropeanAM]

87 is the "minimum" spec fuel. 89 is also acceptable for your engine, but not required.

I would not, however, recommend running anything HIGHER than 89 in your particular engine.

[John Jackson]

The only reservation I have about 89 octane gas is that it is the least amount sold. Which means it gets replaced with fresh gas less often, and there is more of a chance for condensation in the gas station tanks.

[Largemouthlou]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by John Jackson &raquo;</TD></TR><TR><TD CLASS="quote">The only reservation I have about 89 octane gas is that it is the least amount sold. Which means it gets replaced with fresh gas less often, and there is more of a chance for condensation in the gas station tanks.</TD></TR></TABLE>

Not disagreein,,,, I watch the station on the corner and there meters show that 93 is the least sold.. I look for stations that get ne tanks installed and try to bu their 03 for while. But ya kneveer know just how old gas is when ya buy it

[Lpolk]

I always use 89 on my 2006 ProXS. Always have, just thought it was a little better grade.

[nightrider23]

I have a 2005 standard 225 optimax and the marina I go through only has 92 octane non ethanol gas. Is this going to be a problam. I put maybe 20 hours a year on the motor.

[Bobcat]

I asked my local gas station how much '89' they go through. He told me mid-grade is just a mix of regular and premium at the pump. They only have underground tanks for regular and premium. I'm not sure if that is true for all gas stations or not
Bob

[EuropeanAM]

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by nightrider23 &raquo;</TD></TR><TR><TD CLASS="quote">I have a 2005 standard 225 optimax and the marina I go through only has 92 octane non ethanol gas. Is this going to be a problam. I put maybe 20 hours a year on the motor.</TD></TR></TABLE>

If I were in your shoes.... I'd be looking for an "alternative fuel source".

[nightrider23]

Don could you get more specific on the negative effects of 92 octane. I slip my boat at this marina and it's in a remote northern mn lake and I don't really don't have any other options other than to haul my own gas in. If I added a certain amount of 87 to my tanks of 92 would it help.

thanks mark

[EuropeanAM]

These comments apply to running "high test" in an engine THAT DOES NOT SPECIFY HIGH TEST FUEL (based on it's design):

High test fuel burns "cooler and slower" (as compared to regular 87 octane fuel).

Higher octane DOES NOT mean "higher power output".

Since high octane burns cooler and slower, more of the fuel is left unburnt, essentially creating carbon deposits over time. These carbon deposits can cause "hot spots" on the crown of the piston, eventually leading to "premature piston failure".

If your engine was not "designed" for high test fuel, running high test fuel in it is not only a waste of your hard earned dollars, it's "potentially a future waste of many more of your hard earned dollars".

Half high test & half 87 will equal out to "approximately" 89 octane (in most cases). This would certainly be a better choice than running too high an octane.