# Premium Unleaded in Yamaha VMax SHO 225/250



## shallowader (Jul 11, 2009)

Yamaha service manual indicates 87 octane required for SHO 200 but 89 octane for SHO 225 and 250. Who actually uses the premium 89 octane and why? Has anyone had warranty issues or turndowns because of this?


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## blow up (Dec 31, 2011)

I don't think they would.

I would like to hear of a case where they pulled fuel and ran a knock test to determine octane rating. Then prove that the station you bought it at had it marked correctly.


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## Momma's Worry (Aug 3, 2009)

there are no engines,auto or marine, that will self destruct if run on "regular" gasoline.........


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## adpostel (Jan 14, 2006)

I'll be using the Premium in mine when I pick it up. No sense in paying all that money for a boat and then running cheapest gas you can find thru it, thats just my .02 cents tho, and what I'm gonna do...... For what its worth, my F150 has a supercharged 5.4L motor in it, I only put Shell or Exxon 93 octane in it. Runs strong. My wife filled it up last year with regular, ran like a dog the whole tank. I couldn't get on it when I needed the power because the valves would start pinging. Those high compression motors need the higher octane to prevent pinging/detonation. I believe the SHO motors are supercharged, hence the need for the higher octane. I guess if someone was gonna only want to put regular in their boat, they shouldn't get the Supercharged SHO motor. They would be better off getting the regular 4-stroke. What would be the point of getting the higher output motor if you are gonna restrict it anywat...... I got the regular 4-stroke, and it will only see 93 octane......


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## TOOEXTREME (Jun 23, 2004)

89 octane aint premium it is middle grade gasoline. Yamaha recommends middle grade gasoline 89 octane for their SHO motors above 200HP. The Yamaha rep told me you can run 87 octane but you will not get the HP out of the motor because it has knock sensors that will retard the timing when it senses a knock thus reducing HP.


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## shallowader (Jul 11, 2009)

so instead of buying 89 could you add an octane booster


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## Redfishr (Jul 26, 2004)

Guess I'll follow the manuel.


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## InfamousJ (May 21, 2004)

I just follow instructions and use 89 for my 225 sho. I know how bad that regular can be in my truck, don't want that in my boat motor.


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## [email protected]ue (Jun 25, 2005)

SHO motors are not supercharged. The Mercury Verados are supercharged. You may see a slight decrease in HP by running 87 octane. Might as well run 89 to get the most out of your engine.


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## adpostel (Jan 14, 2006)

Good Lookin' out James, I was actually just on the Yamaha site reviewing maintenance information, and one of the things Yamaha recommends is only using the octane recommended for your particular motor. The recommendation for the 225 I have is minimum of 86 octane per the owners manual. The manual states: If knocking or pinging occurs, use a different brand of gasoline or premium unleaded fuel.

Fuel Tips from the website:

​don't regularly exceed 87 octane fuel unless specified by the manufacturer. Using fuel above the recommended octane level for your engine can lead to incomplete combustion and contribute to carbon build up. 

So I guess I'll be using Shell or Exxon 87 octane with fuel stabilizer..... which is a whole 'nuther thread.....


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## yellowskeeter (Jul 18, 2008)

I run regular on mine with 80+ hours and no issues. ran two tanks with premium and I could not personally tell any difference. Dealer told me that there are no issues running regular, just might not get the full hp rating.


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## Capt. Dustin Lee (Jan 16, 2006)

shallowader said:


> so instead of buying 89 could you add an octane booster


From the searching I have done, there really is not a true octane booster on the open market due to lead restrictions. I found this out when looking to see if the octane boosters you buy in the stores would help in my kid's racing ATVs. From what the experts were saying is maybe a .5 or half percent in increase of octane is all you would get and that buying them was more of a waste of money other than if they had any cleaners added to help clean fuel systems or help remove moisture.


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## CaptainJMB (Nov 28, 2008)

[email protected] said:


> SHO motors are not supercharged. The Mercury Verados are supercharged. You may see a slight decrease in HP by running 87 octane. Might as well run 89 to get the most out of your engine.


Very true, the 350 verados Specified 93 octane due to the knock sensors etc. that motor was not capable of retarding the timing and people said " hahaha, I'll show them" and grenades a new 22k motor.

I think we all should get together, buy us a 20k double walled tank on a random location and I can get ethanol free gasoline.

All being said - out of shear curiosity...... If you just spent 20 grand on a new motor..... Or 60 on a new boat/motor package.....it says run 89, why would you go cheap at this point and run anything but?


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## KEMPOC (Aug 24, 2010)

shallowader said:


> Yamaha service manual indicates 87 octane required for SHO 200 but 89 octane for SHO 225 and 250. Who actually uses the premium 89 octane and why? Has anyone had warranty issues or turndowns because of this?


Because *"but 89 octane for SHO 225 and 250" *is reason enough. Having said that, because of my background, I understand how the internal combustion engine works better than most folks. However, I wont waste space in this thread explaining the relationship between compression and octain rating. Google it.

I have heard this topic debated many times, often by guys that dont know what the F they are talking about, and I always have the same thought:

"_Really? You tow a $50K+ fishing rig with a $50K+ truck - full of $700 rod and reel combos while grabbing a cold one out of you $800 Yeti and you are getting chincy over another 20C per gallon to use the manufacturer specified (for good reason) fuel?"_

I am slow - somebody splain it to me!


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## KEMPOC (Aug 24, 2010)

yellowskeeter said:


> I run regular on mine with 80+ hours and no issues. ran two tanks with premium and I could not personally tell any difference. _Dealer told me that there are no issues running regular_, just might not get the full hp rating.


Dealer is wrong.


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## KEMPOC (Aug 24, 2010)

blow up said:


> I don't think they would.
> 
> I would like to hear of a case where they pulled fuel and ran a knock test to determine octane rating. Then prove that the station you bought it at had it marked correctly.


??????


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## shallowader (Jul 11, 2009)

KEMPOC, You seem to have the technical background for the octan rating on fuel. When we buy the 89 unleaded at the station does it lose any of its octane rating over time? Since this fuel usually doesnt turn as fast as the 87 I was just wondering.


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## KEMPOC (Aug 24, 2010)

shallowader said:


> KEMPOC, You seem to have the technical background for the octan rating on fuel. When we buy the 89 unleaded at the station does it lose any of its octane rating over time? Since this fuel usually doesnt turn as fast as the 87 I was just wondering.


Yes it does. And that is the reason for buying at high volume stations. Its tough. The fuel we buy is stored and handled enough that its near impossible to be certain of what you are putting in the tank. Here is another example. My motorcycle has been modified such that I need a high octane fuel. When I can find a 3 hose pump I stop and buy fuel. Unfortunately, many stations have 1 hose for all grades. My bike only holds 6 gal and I am usually pumping 3 or so. At a single hose pump the first .5 gal or so is of the grade that the last buyer selected (still in the hose). 
Sorry - easy answer is that your concern is right on. That is 1 reason I buy from high volume stations.


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## fatrat82 (Feb 27, 2006)

Would it be bad to run super 93 instead of the 89? I have a 250 SHO and have been putting in the super with yamaha fuel additive. I hope I'm not running it with to much extras in my gas!


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## Kyle 1974 (May 10, 2006)

The bad thing about mid grade and super unleaded is that 99% of people run 87, and the higher grades sit in the tank. I put some 93 in my boat last year mixed with 87. That day my water in fuel alarm went off. I'm positive it was due to getting the super unleaded that probably sat in the tank for too long.

I have noticed different performance out of my boat on different days. Probably the fuel. I've tried to track it, but I think it varies even at a single station from week to week. 

Sure would be nice to know exactly what you're getting. 

Will octanes mix? Just wondering if you can fill up at a high volume store with 87, and add enough high octane fuel from a known source to get the right octane.


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## Kyle 1974 (May 10, 2006)

KEMPOC said:


> Because *"but 89 octane for SHO 225 and 250" *is reason enough. Having said that, because of my background, I understand how the internal combustion engine works better than most folks. However, I wont waste space in this thread explaining the relationship between compression and octain rating. Google it.
> 
> I have heard this topic debated many times, often by guys that dont know what the F they are talking about, and I always have the same thought:
> 
> ...


because gas ain't sexy 

I'd put 93 in my boat if I had to, and I knew it was good gas... I just wish I knew where to buy high volume mid grade gas.


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## InfamousJ (May 21, 2004)

Kyle 1974 said:


> I just wish I knew where to buy high volume mid grade gas.


on the water, not the speedy amigo 11 store over the tracks by downtown


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## Kyle 1974 (May 10, 2006)

But they have the best burritos.


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## Court (Jul 16, 2011)

Was told by my dealer to run regular so that's what i've done with no problems & I let them take care of the service-They said I would never have a warranty issue with that.


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## blow up (Dec 31, 2011)

Kyle 1974 said:


> The bad thing about mid grade and super unleaded is that 99% of people run 87, and the higher grades sit in the tank. I put some 93 in my boat last year mixed with 87. That day my water in fuel alarm went off. I'm positive it was due to getting the super unleaded that probably sat in the tank for too long.
> 
> I have noticed different performance out of my boat on different days. Probably the fuel. I've tried to track it, but I think it varies even at a single station from week to week.
> 
> ...


Just buy an octane booster.



KEMPOC said:


> ??????


What's meant by this? Do you know how to determine the octane rating of gasoline, I do.


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## t-tung (Nov 13, 2005)

blow up said:


> Just buy an octane booster.
> 
> What's meant by this? Do you know how to determine the octane rating of gasoline, I do.


Octane booster is snake oil sold at O'Reillys for riceburners. And for the price of that, why not just drop the extra coin on Premium?


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## Bottomsup (Jul 12, 2006)

OK guys octane rating means only one thing and that is its resistance to detonation. The fuel itself doesnt contain more energy or power. In modern computer controlled engines with knock sensors and timing control running less octane fuel will not hurt them due to the computer reducing timing but they will not make full HP. If you feel the need to run wide open at top speed maybe you need a bigger engine. In older or higher compression engines without this control and your asking for broken rings or ring lands on your pistons or in worse cases holes. Where do you get good high octane fuel? From the airport. I wouldnt buy any high octane fuel from a gas station due to its age or water content. Drag racing and owning an aircraft engine manufacturing business for 18 years will teach you all you need to know about fuel but now I am a big diesel enthusiast and dont buy gas except for the lawn mower.


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## shallowminded (May 21, 2004)

I think Kyle is right on the money on the middle and high grades sitting in the service station tanks a long time. I use regular in my SHO 225 and have had no issues. My owners manual state 87 minimum. It is a 2012 model. 

I live in a small town outside of Houston and do not see any people buying the higher grade fuel.

Shallow


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## KEMPOC (Aug 24, 2010)

Bottomsup said:


> OK guys octane rating means only one thing and that is its resistance to detonation. The fuel itself doesnt contain more energy or power. In modern computer controlled engines with knock sensors and timing control running less octane fuel will not hurt them due to the computer reducing timing but they will not make full HP. If you feel the need to run wide open at top speed maybe you need a bigger engine. In older or higher compression engines without this control and your asking for broken rings or ring lands on your pistons or in worse cases holes. Where do you get good high octane fuel? From the airport. I wouldnt buy any high octane fuel from a gas station due to its age or water content. Drag racing and owning an aircraft engine manufacturing business for 18 years will teach you all you need to know about fuel but now I am a big diesel enthusiast and dont buy gas except for the lawn mower.


Correct


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## shallowminded (May 21, 2004)

Now your talking. I can't wait for a turbo charged diesel outboard. Who would have thought 20 years ago we would be where we are now with 4 strokes. Just a matter of time. 

I will straight pipe mine above the water line.

Fun thinking about what is possible.

Shallow


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## Bottomsup (Jul 12, 2006)

Diesel engines will be the future for automotive applications and its sure to take over recreational vehicles as well. Mark my words. Gasoline will be a thing a thing of the past and there will be no alternative fuels widely available until fossil fuels are gone.


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## FAT TIRE (Nov 25, 2004)

shallowminded said:


> Now your talking. I can't wait for a turbo charged diesel outboard. Who would have thought 20 years ago we would be where we are now with 4 strokes. Just a matter of time.
> 
> I will straight pipe mine above the water line.
> 
> ...


LMAO it would weigh about 900lbs after the EPA got there hands on it. Can you imagine an outboard with a cat, DPF, and a tank under the console for the diesel exhaust fluid:headknock


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## Trouthunter (Dec 18, 1998)

> I know how bad that regular can be in my truck, don't want that in my boat motor


Then you need to get a new truck.



TH


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## BBKing (May 22, 2010)

High octane gas can cause a problem with 2 strokes. The higher the octane the slower the burn and 2 strokes have only half the time to eliminate un-burnt gas as compared to 4 strokes. I don't think there would be a problem running the higher octane in a 4 stroke.


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## Bottomsup (Jul 12, 2006)

BBKing said:


> High octane gas can cause a problem with 2 strokes. The higher the octane the slower the burn and 2 strokes have only half the time to eliminate un-burnt gas as compared to 4 strokes. I don't think there would be a problem running the higher octane in a 4 stroke.


According to the petroleum manufacturers higher octane fuel does not burn slower. Octane rating is strictly the fuels resistance to detonation. I always felt like it did burn a little slower but had no way to test or prove it. I felt like the engines I produced ran hotter on higher octane with no ignition timing change. With a small ignition timing change as to advance the timing to take advantage of the higher octane fuel and power output the engine would run hotter because it was working harder and producing more power.


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## BBKing (May 22, 2010)

I did a quick search to see if I had misstated that high octane gas burns slower than lower octane gas. Here is what I found:

http://mn.gov/commerce/weights-and-measures/images/OctaneFacts.pdf

Scroll done to the second item under "Octane Facts". This is from our Government so it's got to be right. Well, maybe this time?


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## cfulbright (Jun 24, 2009)

Octane rating is strictly the fuels resistance to detonation. = BURNS SLOWER.

This is what you need to know, use the gas the engine was built to run on. that's it!

The compression in the motor is what determines what gas to run. Higher compression=more octane needed(on naturally aspirated engines).


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## Bottomsup (Jul 12, 2006)

cfulbright said:


> Octane rating is strictly the fuels resistance to detonation. = BURNS SLOWER.
> 
> This is what you need to know, use the gas the engine was built to run on. that's it!
> 
> The compression in the motor is what determines what gas to run. Higher compression=more octane needed(on naturally aspirated engines).


Compression is not the only factor. Any engine with to much ignition timing will also have issues with to low octane fuel.


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## Kyle 1974 (May 10, 2006)

bringing this back up... regarding buying av gas from the airport was listed as 100 octane.. is this correct? not a refined fuels guy here... so running 100 octane in a modern outboard would do what?


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## mgeistman (Jun 13, 2012)

Well first off that fuel has lead in it. The lead will ruin your o2 sensors. Octane is a detergent, which makes the fuel less explosive when under compression which is why high compression race engines/airplanes use it. It helps keep predetonation under control and temps down. I would not recommend the use of leaded fuel in a engine with o2 sensors. On a carbed engine it's ok to run, but of you don't have high compression you will loose power. Enough to feel while behind the wheel? Prolly not.


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## mgeistman (Jun 13, 2012)

I use it in all my small engines, mower and fourwheeler, ect. Leaded high octane fuel will last WAY longer than regular pump gas will.


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## PHINS (May 25, 2004)

shallowminded said:


> Now your talking. I can't wait for a turbo charged diesel outboard. Who would have thought 20 years ago we would be where we are now with 4 strokes. Just a matter of time.
> 
> I will straight pipe mine above the water line.
> 
> ...


http://coxmarine.com

Sent from my iPhone using Tapatalk


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## RedXCross (Aug 7, 2005)

Getting it here in the US and having it serviced might be a booger?



PHINS said:


> http://coxmarine.com
> 
> Sent from my iPhone using Tapatalk


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