Octane to use in Boat

[shemakesmesmile]

Ethanol free is definitely the way to go.

I see you're in East Troy, what lakes do you go to? We live about a mile off of Whitewater Lake and usually go there or Lauderdale Lakes.

[Wagonhound]

I've been involved in the fuel industry almost my entire life (my dad sold Chevron, Conoco, Mobil, you name, it so I learned a thing or two) and currently I am regulator in fuel industry. Higher octane fuel is needed when you are running a high compression engine or at lower altitudes (more oxygen). If you run your Tige in WI you probably need and 89, but if you bring it into the Rocky Mountains you'd only need 85. If your engine runs without "knocking" using 89 octane, a 91 will have absolutely no benefit.
There are a lot of myths about ethanol fuel, but in actuality modern day engines of about every type are designed to run on ethanol fuel, with the exception of high compression outboards. The biggest advantage to non-ethanol fuel is of course long term storage. Avgas is non-ethanol for that exact reason, and rated at 100-110 for, of course, high compression engines. Snowmobile manufacturers have even amped up their game and have not required non-ethanol fuel in quite some time, and they are far higher compression than in our Tige's. I've never had problems running ethanol fuel in either my Seadoos or Skidoo and don't know anyone who has. You're more likely to get bad fuel from poorly managed underground fuel tanks than from too much ethanol.

http://www.westmarine.com/WestAdviso...nol-Fuel-Myths

[IDBoating]

It's not a question of whether engines will be damaged by running on ethanol fuel. Agreed that all modern engines handle at least E10 properly, and their manuals say so.

The problem is ethanol's affinity for water, and the damage that can result to fuel systems (tanks, lines, pumps, filters, etc.) particularly to infrequent use engines such as marine and other sport applications, where the fuel may sit for days or weeks as compared to a daily driver land vehicle. I'm not interested in encouraging water in the fuel systems of my many casual use engines (boat, jetskis, ATV's, hand tools, etc.).

That's why I avoid ethanol fuel for those engines. In my wife's minivan, no problem. We buy whatever regular grade gasoline is offered because we cycle through that fuel regularly. But I'm much pickier for the casual use engines... no ethanol for them, period.

[TeamAllen]

My understanding is that ethanol fuel also has a lower vaporizing point. That is the only problem I experienced in my older 97 boat. It was causing vapor lock.

Of course the long term storage issue is a problem for any situation.

[BCRider]

2011 PCM owners manual. I only post a 2011 because I have an 09 so everything is relevant to my motor at least and is the digital copy I have. Not sure about some of the new ones some of you may have.

[Wagonhound]

If it's any consolation, Ted Cruz said he will not support the subsidizing of ethanol fuel. In Wyoming, they just shut the only ethanol plant down because they couldn't compete with the price of crude even with the subsidy. Trump probably doesn't like running bio-diesel in his yacht, so hopefully one of them will get elected and solve our ethanol problem.

[dom w. forte]

Also the 2014 boats and up now have sealed tanks with evap systems, this is a major breakthrough for boats because they wont tend took suck in condensation like the older vented tanks.

[Andy454]

My understanding is that ethanol fuel also has a lower vaporizing point. That is the only problem I experienced in my older 97 boat. It was causing vapor lock.

Of course the long term storage issue is a problem for any situation.

Mercruser had fuel vaporizing issues with the older fuel injected boats, their Vapor Separator Tank (VST) inherently had problems because it got hot and vaporized the gas. They tried to fix it with a different fuel pump, but it still did it once in a while.

[whiteflash watersports]

I have run nothing but 87 octane with ethanol in our 343 pcm since day one. We have over 600 hrs and not a single issue. I run a full can of seafoam thru every 6 months.

[mdk681]

I am confused a bit - so I typically run standard 87 octane pump gas in my 99 21v's 350 MAG MPI. We have special pumps at gas stations around the lake that are non-oxy 91 octane fuel, we use that in our snowmobiles/ice auger/lawn mower, etc. Is non-oxy the same as ethanol free? Is it worth while to run the non-oxy 91 octane in my boat...?

[Stingreye]

After I told Boatwakes that the manual said to use 87 in my PCM 6L motor. He said said that's odd, all the LS style 6L motors generally are tuned to run on 89 (or something close to that). I called PCM they said 87 can be used on the 6L (as stated in the manual) but that 89 is optimal for that engine (its "tuned" for 89) just like every other brand of 6L LS style motor, with 87 the ECU is adjusting the timing to compensate for the drop in octane.

Basically, I get 89 when I can but don't worry about getting 87 if its the only option. As far as I know, I don't think ethanol free gas is available anywhere i southern california.

[chpthril]

2 pages of good info, debate and opinions, but since the OP has not come back to confirm what engine he has, its all academic and theory

[smp9813]

Sorry for Just replying to you all. Been a busy week. We took out the boat on Friday and before going I filled it up in East Troy and got ethanol free 89 octane. The boat ran great, filled it up with weight to make sure and everything seemed to be fine. Also I have the 2014 Indmar 5.7 engine. Attached a picture of her all cleaned up. Attach2458_20160506_124138.jpg

[smp9813]

Ethanol free is definitely the way to go.

I see you're in East Troy, what lakes do you go to? We live about a mile off of Whitewater Lake and usually go there or Lauderdale Lakes.

We go on Lake Beulah. We have a Slip in front of Lindeys. We love it out there.