What type of Gas are you running in your boat?

[OCMD]

Non-eth. Always. Although on my LS I ran whatver was the lowest price, and never had an issue.

 

[viper15]

Not really sure if my vote will be valid info for what you may be looking for. My boat is the supercharged AR195. Because of the boost, I run the recommended higher octane. History .... I've run many, many of Yamaha four-stroke snowmobiles over the past 10 years. For their NA engines, 87 octane is plenty. I even joke that you could dump crude oil in them and they would run fine. LOVE YAMAHA ENGINES! But when it comes to boost, that's a different story. My latest snowmobile is still a Yamaha, but with an aftermarket turbo running 6+ lbs of boost. What a wild ride that is! But in the world of boosted snowmobiles, I've seen too many engines go BOOM because of running too lean, bad gas, or too low of an octane (pre-detonation). So, I try to follow the same gas methods on my boosted jetboat. Also, since I don't run my boat every day (many times it sits for a week+ between uses) I try to still to 100% gas simply to avoid water collection in the tank.

 

[sysinu]

Never take your boat from low altitude and fuel up with ethanol and transport the boat to high altitude. That will be one of the most frustrating experiences you can ever have. I fueled up in Page AZ, ran the boat around at lake powell but didn't go too far up lake. Then went from the 3500' altitude with a partially (3/4 tank) full tank of 87 octane 10% Ethanol gas to 6600' altitude and ended up having to filter out 3+ gallons of water from my 40 gallons of fuel.

Also, I totally loved being that guy at the ramp a month later (clean drain dry requirements for quagga) at the local lake trying to start my boat. I hate hate hate Ethanol fuel.

 

[swatski]

Never take your boat from low altitude and fuel up with ethanol and transport the boat to high altitude. That will be one of the most frustrating experiences you can ever have. I fueled up in Page AZ, ran the boat around at lake powell but didn't go too far up lake. Then went from the 3500' altitude with a partially (3/4 tank) full tank of 87 octane 10% Ethanol gas to 6600' altitude and ended up having to filter out 3+ gallons of water from my 40 gallons of fuel.

Also, I totally loved being that guy at the ramp a month later (clean drain dry requirements for quagga) at the local lake trying to start my boat. I hate hate hate Ethanol fuel.

Huh! That's a good reminder/refresher about the wonders of high altitude boating!

Normally, ethanol is added, in part, to boost octane numbers in fuel. However, at high altitude low octane fuel is fine because even though the static compression ratio of a given engine remains the same, the pressure developed during compression is lower at higher altitude. This is simply due to the lower initial pressure of the atmosphere (lower compression pressure means lower octane requirement). So - there is hardly a positive for ethanol at high altitude.

But - to make it worse - in the presence of water ethanol acts like a detergent: water molecules get surrounded by the polar heads of the ethanol at the same time pointing the aliphatic tails towards the gasoline environment. So - gasoline with ethanol can absorb a lot of water - for example from humid air, in addition to normal condensation cycles - worse in partially filled tank. And when the temperature drops... that water can subsequently separate... Ouch!

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[sysinu]

Huh! That's a good reminder/refresher about the wonders of high altitude boating!

Normally, ethanol is added, in part, to boost octane numbers in fuel. However, at high altitude low octane fuel is fine because even though the static compression ratio of a given engine remains the same, the pressure developed during compression is lower at higher altitude. This is simply due to the lower initial pressure of the atmosphere (lower compression pressure means lower octane requirement). So - there is hardly a positive for ethanol at high altitude.

But - to make it worse - in the presence of water ethanol acts like a detergent: water molecules get surrounded by the polar heads of the ethanol at the same time pointing the aliphatic tails towards the gasoline environment. So - gasoline with ethanol can absorb a lot of water - for example from humid air, in addition to normal condensation cycles - worse in partially filled tank. And when the temperature drops... that water can subsequently separate... Ouch!

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This is great info. I should add... it ends up looking like this (I had 4 5 gallon tanks that looked like this. And no, I didn’t take them back to Home Depot for a refill):

 

[zipper]

Wow, glad I used non ethanol all season. The marina we slipped at has fuel, only non ethenol. Long lines on the weekends, so we usually fueled up on weekdays to take advantage of the members only 20% discount. When trailering, I will use E10 with an additive if non ethanol is not available. However there is one pump in town that has 91 non ethenol, I try to fuel up there when their tight access to pumps is not busy.

 

[Cobra Jet Steering LLC]

I run regular from the pump with ethanol but skies use a different venting than the boats do and the vent is where most of the moisture gets access to your fuel.
I am obviously at sea level however our humidity is atrocious. I also add fuel injector cleaner in my fuel every month or so just to keep those clean.
Never had any issues yet with water in the fuel. however I trailer my skies.
I have had issues with water in the fuel with boats, usually due to the location of the fuel vents, I learned to make a self draining adaptor for boats with the vents in a location where the hull can cause water to contact the vent openings on the outside of the hull either by flowing up the front of the hull or in the back of the boat where back wash can get to the vent openings.
A self draining adaptor is just a chamber where the fitting exiting the hull attaches below it and the hose to the tank attaches on top of it so any water would just drain back out the vent fitting. I made these about 35 years ago when people kept having issues with boats getting water in the fuel, one look at the location of the vents on some boats and the routing of the vent hoses showed the problem even with a loop in the hose that was commonly used will not always work if you are running a lot of fuel at speed and creating a vacuum in the fuel tank as it can suck in the water collecting in the loop. So having a larger void where the water stays on the bottom draining back out and air exits the top going to the fuel tank worked nicely.

 

[djetok]

I have always ran ethanol free, why. Because dad said too!!! I will run some lucas after I burn off my first tank of the season with all the stabil in it.

 

[swatski]

A self draining adaptor is just a chamber where the fitting exiting the hull attaches below it and the hose to the tank attaches on top of it so any water would just drain back out the vent fitting. I made these about 35 years ago when people kept having issues with boats getting water in the fuel, one look at the location of the vents on some boats and the routing of the vent hoses showed the problem even with a loop in the hose that was commonly used will not always work if you are running a lot of fuel at speed and creating a vacuum in the fuel tank as it can suck in the water collecting in the loop. So having a larger void where the water stays on the bottom draining back out and air exits the top going to the fuel tank worked nicely.

Cool idea with the adaptor! But all the new Yammies have the fuel vent in front of the gas cap and they already have fuel vapor traps built-in the vent line (presumably filled with activated carbon) - big and ugly and located by the batteries - which I guess could be drain-able. I had to move mine to free up some space for ballast bags so I had a really good look at it.

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[Cobra Jet Steering LLC]

So what happens to the water vapor that gets in the fuel tank? if the temperature drops it condenses, Alcohol will mix instantly with water and then mix with your fuel so I see why people do not want to use alcohol in their fuel.
Now I recall back at the start of adding alcohol to gas there was a time when alcohol in the fuel messed with the seals and gaskets this has been addressed I am told.
Once upon a time people intentionally injected water into their gas engines to increase the engines power. There was also a time that someone I know would hook up a water injector to an old dodge van to pass emissions and the people tried to figure out how on earth this old van could possibly get the readings so low with a 360 carbureted engine , but it passed every time Umm so I was told!!!
So in the end I believe those who use regular fuel and have no issues with it will continue to use it and those that don't won't based on similar questions asked in the past.

 

[Weeb]

Im running 87 non ethanol right now trailering and I believe the mariner that I'll put it at has 87 or 89 non ethanol. I've had to many issues with the corn syrup over the years.

 

[Beachbummer]

On my carbed sea-doo when Ethanol fuel came out I had a horrible year. Spin on Fuel Water separators in SERIES fixed all present and future problems with water in fuel, and dirt being lifted by the ethanol in the fuel. It's a modification I have not yet made to the Yamaha...but one I'm considering. I'm not too excited by the fact the filter would be on the high pressure side of the system, hence my hesitation.

 

[Cobra Jet Steering LLC]

I do not believe you will actually need it, your problem arose from a change from using regular fuel to ethanol fuel the system had items that were left behind from the old type fuel and additives in that fuel, if you are running only the ethanol fuel I do not believe you will have those issues. Also you said the name SEA DOO they had the worst reputation for fuel lines gumming up the fuel systems I always removed the original fuel lines when I owned those.

 

[Beachbummer]

I do not believe you will actually need it, your problem arose from a change from using regular fuel to ethanol fuel the system had items that were left behind from the old type fuel and additives in that fuel, if you are running only the ethanol fuel I do not believe you will have those issues. Also you said the name SEA DOO they had the worst reputation for fuel lines gumming up the fuel systems I always removed the original fuel lines when I owned those.

Thankfully mine was after the fiasco, they had not used those tempo gray lines on mine...but the Ethanol still killed me. I agree with your thoughts on always ethanol, so hopefully not an issue.

 

[LeeFlan7]

hmmm, this thread has got me thinking, my usual fill up station only sells treated 93 octane (on the water), i tried to find my owners manual for the 17 sx210 but i must have left it in the glovebox for winter storage...does anyone know the recommended octane for me?
and would this affect the boat in any way if im putting in gas that the octane is too high?

 

[Cobra Jet Steering LLC]

Just basically a waste of money since the higher the octane the slower the fuel burns and if the timing is not correct for the octane your timing is too late so you won't gain the full power of the fuel .

 

[LeeFlan7]

@Cobra Jet Steering LLC so, if it calls for 87, in theory i could get a little better performance with that?

 

[Cobra Jet Steering LLC]

Possibly since the fuel is being ignited at the correct time and burning completely where you are wasting money using a higher octane that what the timing was set for.

 

[LeeFlan7]

damn!! haha, ill get this figured out eventually, is there anywhere online to find yamaha owners manuals so I can check the correct octane?

Update...i found and downloaded the owners manual, it says the boat should be run on regular unleaded gasoline with a minimum octane rating of 86...but goes on to read "(pump octane number) = (r+m)/2 90 (research octane number)" what does that mean??

 

[Cobra Jet Steering LLC]

Do you have a regular 1800 engine because as far as I know they run on regular gas 87 supercharged use a higher octane I believe 91