octane rating for a 25 hp merc

[missed_shot]

I have a 2003 - 25 hp. Merc. I was told by the dealer to only use 89 octane gas. Is this true or can I use 87 octane with no problem or noticable difference??

 

[rickdb1boat]

Re: octane rating for a 25 hp merc

87 will be just fine. No need to waste your money on higher octane, as it will be of no advantage..

 

[missed_shot]

Re: octane rating for a 25 hp merc

Thanks rickboat- With the price of gas, I would like to go as cheap as I can .

 

[JB]

Re: octane rating for a 25 hp merc

Moving to General Outboard

 

[quantumleap]

Re: octane rating for a 25 hp merc

In many areas of the country, 89 octane, or midgrades, contain up to 10% alcohol. I would not use an alcohol blended gas in an outboard motor.

 

[ZmOz]

Re: octane rating for a 25 hp merc

Anywhere that has alcohol in the mid grade gas also has it in the regular and most likely premium. Mid grade is mixed right at the pump from the regular and premium, there fore it cannot be the only grade with alcohol in it. Alcoholic gas is just fine to use in an outboard as it is in any other engine, it just doesn't give as good of fuel economy and can be harder on seals and fuel lines.

 

[Old Jarhead]

Re: octane rating for a 25 hp merc

I own a 2003 25hp Mercury. The owners manual saids to use, as well as the dealer who sold it to me, 89 octane fuel... so I use 89 octane fuel.<br /><br />Seems like a no brainer to me.

 

[Fishin Rod]

Re: octane rating for a 25 hp merc

Hmmm.. The difference in price between 87 and 89 octane is about 10¢ a gallon right? <br />I don't know how much gas your 25hp uses a day but I doubt it's over a (6 gallon) tank. That's a whopping 60¢.<br /><br />Buy one less beer (can you still buy a beer for 60¢?) for the day and burn the right gas.<br /><br />Just my 2¢.

 

[quantumleap]

Re: octane rating for a 25 hp merc

Wrong again Oz- In the state I live the government requires that any fuel containing alcohol be posted so at the pump. The migrade, 89 octane fuel here is a 10% ethanol blend with the regular 87 octane and premium 91 and 92 octane containing NO alcohol. I would very much like to see facts to support the claim that midgrade is mixed at the pump!! Not in my part of the world!

Alcoholic gas is just fine to use in an outboard as it is in any other engine, it just doesn't give as good of fuel economy and can be harder on seals and fuel lines.

Why would you want to use a fuel that can be 'hard on seals and fuel lines' that doesn't 'give as good of fuel economy' if there is an alternative at the same pump?<br />(edit)

 

[ZmOz]

Re: octane rating for a 25 hp merc

Sure, if there was an alternative at the pump I wouldn't use gas with alcohol. It's crap no matter how you look at it. I will bet you $50,000 that your 89 is not the only one with alochol. First of all, ALL gas stations only have two grades, regular and premium. Mid grade is mixed right at the pump - that is a fact! Second of all, WHY would they only put it in the mid grade? That doesn't make any sense. It's there to reduce pollution, there fore they put it in the most used grade - 87. Some places (very few) do have non oxygenated PREMIUM, there fore the mid grade has less alchol because it is mixed with premium. <br /><br />Please, Quantumleap, don't tell me I'm wrong until you have a clue what you're talking about.

 

[quantumleap]

Re: octane rating for a 25 hp merc

Oz, I just explained that in many, if not most states, the law states that stations must display which fuels contain alcohol and that display must be on the sticker that indicates the octane level and alcohol content of the gasoline coming out of that particular pump.

First of all, ALL gas stations only have two grades, regular and premium. Mid grade is mixed right at the pump - that is a fact!

Please support the above referenced claim. or better yet let me correct you, I just called a friend who worked for years for the largest Petroleum franchise in my city and he verified that yes, the midgrade is indeed a separate product. The only of the three in my area that contain Ethanol.<br /> <br />Now, it may be entirely possible that the state in which you live has different regulations and methods of dispensing fuels, but please don't try to tell me that I'm wrong about the gasoline types and regulations in my area.<br /><br />I am going to politely ask that from now on you please stop harassing my post and replies on the subject of fuels. Or any other subject for that matter. But before we part ways, you can e-mail me direct and I can give you my address to send the check for $50,000. Thank you for the contribution.

 

[ZmOz]

Re: octane rating for a 25 hp merc

I'm not "harrasing" your posts. I'm correcting your information so others on the forum that don't know better don't read it and use it as a fact. I'm not going to spend an hour writing a friggin' bibliography for you just because you want 'facts'.

 

[quantumleap]

Re: octane rating for a 25 hp merc

please stop, you're making yourself look silly again.

 

[ZmOz]

Re: octane rating for a 25 hp merc

I love how that's your answer every time you no longer have an arguement. Yeah, I'm the one that looks silly...

 

[cobra 3.0]

Re: octane rating for a 25 hp merc

My daddy's stronger than your daddy!

 

[quantumleap]

Re: octane rating for a 25 hp merc

... and again. Please, Please show me one little shred of proof to back up your claim that 87 octane gas is also an alcohol blend. According to your ridiculous theory that 89 is a mix of premium and regular, then if 89 octane is listed as 10% ethanol blend, 87 octane would have to be a higher percentage of Ethanol, which is illegal to sell!! Please explain how this is possible???

 

[quantumleap]

Re: octane rating for a 25 hp merc

cobra- I know, I know, I need to let it go. Does anyone else reading this post have any problem with Oz's theory that all low to mid grade fuels are an alcohol blend??