Fuel Question (Old Timers vs. The Manual)

[King]

We're still waiting for our 212S to arrive. Doing tons of prep work in anticipation. Some of that includes discussions with current and former boat owners. This discrepancy between advise and what's in the Yamaha manual usually comes from the older, former owners, group that know nothing of Yamaha other than outboards and think of wings and the great blue sky when you say "Jet".

Don't use anything but ethanol free gas!!!

Well, it's my understanding that for the 1.8l NA engines, 87 (R+M/2) Octane with <10% ethanol (not methanol) is perfectly fine. However, I've been hit with; don't use anything but ethanol free gas, one time too many times and I'm now second guessing my ability to read and comprehend the Yamaha manual for the 2022 212S when it comes to fuel selection.



What's the opinion of you all, those in the know? Is the 90/91/93 Octane Ethanol Free stuff that's a buck or two more a gallon needed, or even worth it, in the NA engines?

 

[mwalker4]

The ethanol doesn't impact the engine directly like older engines, but it does react with water over time. So I use normal gas during the season and fill it up with ethanol free before storage. I use gas treatment with every tank.

 

[Murf'n'surf]

I would use standard pump gas when the boat was being used on the regular. If it was going to sit a while, the non ethanol was was purchased to avoid the water separation issue.

 

[AmesJainchill]

I personally use only Valvtect E0 and no other additives as it already has enough. Never had any fuel issues. If I could find that in 87 octane that would be perfect and probably give better speed/performance since the NA engines aren't tuned for the higher octane afaik.. Of course it's probably a lot pricier than going with E10 Regular plus some Yamaha Engine MedRX which is what I think the manual recommended. Could probably go Rec Gas E0 on the road with the occassional MedRX additive - though any E0 tends to be pretty pricey as well from what I've seen. At the end of the day, I'm probably just neurotic/ocd in my need to only use Valvtect.

 

[CarolinaJet]

I follow what is in the manual, 87 pump octane. The people who told me to only put ethanol free in my boat are the same people who ignored the break in process during the test ride until I told them to back off, then they told me to run it hard to seat something or other. The old ‘break it in fast so it’ll run fast’ logic. So they shot their credibility. This is a modern engine designed for fuels that include ethanol.

 

[adrianp89]

Yamaha > Old geezer

So many people think they know best and they have no idea. They just spew whatever they were told in the 70s.

 

[Zizzou 192]

Definitely use the fuels recommended in the individual boat’s manual.

The ethanol portion of gas does however contain about 30% less energy than an equal amount of gasoline.

The shelf life of gasoline without ethanol is about 6 months, compared to 3 months with ethanol.

 

[Julian]

Been running gas with ethanol in three different Yamaha jet boats with no ill effect for nearly 20 years.

 

[biffdotorg]

People that ignore the advice in a Yamaha owners manual confuse me. They were an engine builder before a boat builder, snowmobile builder, ATV builder and I have run ethanol in all of the above from yamaha with no ill effects. MWalker hit the nail on the head. Be careful when storing, and you will be fine.

 

[Beachcampin]

I would be careful this year. The US government is giving waivers for amounts of ethanol that may be in fuel this summer. The coast guard has been worried that the labeling requirements may be waived or will not be clear for boaters. Avoid E15, but the labels apparently are not always clear due to the way it’s marketed.

Whoa, Boaters! Slow Down on the Recent E15 News : BoatUS News Room

It may not be as good as you think

www.boatus.com

 

[CarolinaJet]

I would be careful this year. The US government is giving waivers for amounts of ethanol that may be in fuel this summer. The coast guard has been worried that the labeling requirements may be waived or will not be clear for boaters. Avoid E15, but the labels apparently are not always clear due to the way it’s marketed.

Whoa, Boaters! Slow Down on the Recent E15 News : BoatUS News Room

It may not be as good as you think

www.boatus.com

Thanks for the tip!

 

[King]

Thank you everyone!

You've confirmed what I've read, confirmed what I assumed, and got me up to speed on new aspects I didn't even think of.

While in play, I'll feed her the 87 stuff that's friendly on the pocketbook along with some treatment additives.

While in storage, going with the ValvTect that @AmesJainchill suggests. There's at least two marinas on my home lake that offer it.

 

[Dave burke]

Great info all. Can I briefly highjack this thread? I tend to use 91 octane because it feels to me like the engines run better. What do others do?

 

[FSH 210 Sport]

My two cents…

The manual calls for a minimum of 86 octane, same as with mine and that’s what I run. I mix 85 and 91 non ethanol in the proper ratio to get 86 octane.

Octane Mixture Calculator

If you are going to ethanol laced fuel then you should always run a stabilizer like Star Tron to prevent phase separation. The biggest problem with ethanol in gasoline is that ethanol bonds instantly with water, and you don’t know how much water is in the fuel you buy in the first place. The second biggest problem is that ethanol laced fuel has less btu’s per gallon than straight / non ethanol gas as @Zizzou 192 stated.

Since we are in a very wet environment water is eventually going to get into the fuel tank, if you’re running ethanol this water is going to get absorbed by that ethanol. What is not known is what the water load of the fuel is before the additional water is introduced. Too much water load and the water / ethanol mix drops out out of suspension aka phase separation, which is like a sludge. On the flip side, if running non ethanol fuel it’s a good idea to run some ethanol / fuel system water remover once in a while.

Having said that, I lost a fuel pressure regulator on one of my fuel injected dirt bikes due to corrosion caused by ethanol laced fuel, I lost a day of riding as this occurred after I drove 2.5 hours to my riding area, and spent a week trying to figure out what it was. After that I always ran Star Tron additive to protect the fuel system from ethanol laced fuel issues. At that time I did not have access to non ethanol fuel other than prohibitively expensive race gas.

Now that I have access to non ethanol fuel that is all I run in everything I own ( boat, dirt bikes, rv generator tank, riding mower, leaf blower, weed whacker) that is gasoline powered to prevent the problems associated with ethanol laced fuel namely phase separation and corrosion. Will I run 87 ethanol laced fuel if that’s all I can get? Sure, but I will come back home with as little of that in the tank as possible and run the tank down really low and then go re fill with non ethanol.

The difference in price for a 40 gallon fill up is $8, well worth the added expense in my opinion, no water attracting problems, much longer shelf life, more btu’s per gallon.

I find it fascinating at best how there are “waivers” being given to put 15% ethanol in motor vehicle gasoline during the summer. If you notice on the pump label it states “up to 10%“ ethanol currently. That is because there is less ethanol put in during the summer because it causes greater emissions. Also, it is against federal law for marine gasoline to have greater than 10% ethanol in it. Ethanol is touted as as an additive to promote less emissions, yet it takes 1.3 units of energy in to get 1 unit of energy out of ethanol, and it is produced using primarily diesel fuel. In reality ethanol is used as an anti knock / detonation additive / octane improver. Makes me wonder what anti knock compound is being used during the summer. Ethanol replaced MTBE, and MTBE replaced tetraethyl lead as anti knock improvers. Another example of Agribusiness profiting from Govt regulation. And! Only a govt could mandate higher mpg vehicles while at the same time mandating the use of a fuel that has less energy in it. You just can’t make this stuff up.

 

[FSH 210 Sport]

Great info all. Can I briefly highjack this thread? I tend to use 91 octane because it feels to me like the engines run better. What do others do?

If your engine requires 86 octane fuel and you are using 91 then not only are you wasting your money, you are getting less power and your cylinder temps are much higher.

 

[Matt Phillips]

I've run whatever is at the gas dock pump that's unleaded regular in 2 yamaha's for the past 10 seasons...as usually on the water there's not a choice. I do however add Stabil Marine to every tank. No problems. The NA engines I've had aren't picky and will drink what ya feed them...so long as it's not diesel and above the minimum octane rating.

 

[seanmclean]

87E10 (if naturally aspirated), end of thread. Anything beyond that is old timer nonsense and 'seat of pants' dyno BS.

No fuel treatment required if being regularly used, but sure doesn't hurt. Once in season I'm burning it fast enough not to bother, and stabil for the winter

 

[Babin Farms]

 

[biffdotorg]

This comes up so often, but even more when gas is so expensive. The 91 octane enthusiasts start to question their fuel choice logic.

BTW, our local pumps shut off at $175. I didn't think I would ever need to know that. I was wrong with 6 more gallons left to pump.

PS: I took a half hour at lunch to "drop the kid off at the pool" She's on the lift now and ready to rock!

 

[Dave burke]

Thx guys. 87 it is. The savings will go into the beer cooler.