Pontoon Boat & Deck Boat Forum

Was servicing my OB a couple days ago, oil change, lower unit, prop, ect.
pulled the cowling off and damn the fuel filter was black. I took it to the people
I have work on the motor to have the impeller changed. Any hoo the primer bulb
was rotting from the inside out. Got to be alert all the time. Regards, old jim

90/10 gasoline is death on anything that's rubber. That also includes rubber membranes in fuel pumps on 2 stroke outboards.

I would think newer fuel lines and bulbs would be out of different materials.

[quote="Bamaman"]90/10 gasoline is death on anything that's rubber. [/quote]


That right there is the reason I will drive 15 miles out of my way to gas my boat up at a station that sells ethanol free gas... yeah it's a pia to go completely out of my way to buy the E-Free gas, but fortunately I never have to fill up more than twice in a season so it's not a huge deal. with that and using a good stabilizer, so far I've been lucky, no issues that I'm aware of...

I agree, I use nothing but Shell Ultimate 92 octane in everything. If I must use ethanol, I dump in Stabil's Ethanol fuel treatment. I've seen 1 year old fuel lines degregate and plug off with ethanol use. We make ethanol at the plant I work at, as by-product from cracking Natural Gas, to make plastic polymer. We save some of the ethanol and when our reaction towers foul, we coat the inside of the towers with ionized ethanol and fire them off. if this stuff will coat and adhere to our towers, think of whet continued use does to fuel systems. Nasty stuff....

I would like to know what the deal is-

I can understand a motor/fuel system from years ago not being able to handle the 10% ethanol, but how long has ethanol been in play in automotive fuel systems? I use regular(?) Sta-bil in my snow-thrower and generator fuel with ethanol. Earlier this year the generator's fuel was 5 years old when I replaced it. It started/ran every time I needed it or tested it and there wasn't a problem, but being a generator, I thought 5 years was long enough

Our 1999 Johnson claims to be able to handle up to 10% ethanol. I would think boat fuel systems would long have been hardware ready for ethanol for many years. That being said, I haven't ran any ethanol in our pontoon, but I don't think any marina on the lake offers ethanol, either.

Just curious...

[quote="urbnsr"]I would like to know what the deal is-

I can understand a motor/fuel system from years ago not being able to handle the 10% ethanol,.[/quote]

I'm not a mechanic by any means, but my understanding is that E-10 fuel eat away at the rubber components in the system, not necessarily the engine itself... things like fuel lines etc.. or at least that's what has been told to me.

The last few years I have had to stop using 'hamburger helper' gas (ethanol) in the weed eaters and lawn mower. The stuff ate up the weed eaters primer bulbs and other rubber. I will never use it in the boat. I had a Yamaha Vmax motorcycle and made the mistake of using the watered down gas in the bike and didn't ride it for a month or so and all 4 carbs had to be rebuilt.

Yes, those examples are what I am hearing from many people, but it's not what I am finding - at least not in the garage. If you guys aren't using Sta-bil (or equivalent), then that stuff must be great.

I've had a mower since 1996 with a primer bulb, 2 stroke trimmer with primer bulb for 10 years now, newer 2 stroke leaf blower and that generator. All sta-bil, all 10% ethanol, zero fuel problems. I do try to fill the fuel tanks as much as possible when the item goes to out-of-season status. Again - that generator had 5 year old gas. I used to test run the generator every month, but have to admit that the tests are now more like twice a year. It starts up with one or two pulls and no hesitation.

I can imagine the ethanol eating the rubber, but I have to go back to the idea that ethanol has been around for many years that manufactures, and part suppliers should have cycled out the affected parts by now.

The new mercury manuals state ethanol added fuel is just fine up to 10 or 15%...can't remember the exact percentage. We run our boat at least a couple hundred hours a year and it rarely sits more than a week. I do run stabil marine 360 in all gas that goes in just to be safe. From what I've heard switching back and forth between non ethanol and ethanol fuel can actually cause more issues than running 10-15% ethanol from day one. Just like newer cars, new boats that are well built use hoses, filters, etc that are safe for ethanol fuels.

Our 1999 Johnson manual indicates that up to 10% ethanol is acceptable. That was in 1999.

I did read an article about switching to ethanol supplemented fuel and they recommended evacuating the fuel tank because of the accumulating water in the bottom of the tank using straight gasoline. When switching to ethanol added fuel, the alcohol attempts to take the accumulating water along and it's too much water to run the motor. The article may have mentioned adding a water separator (at least temporarily) to catch any remaining water. With continued use of ethanol, the ethanol keeps up with the invading water. At least, that's my interpretation of the issue.

http://www.pure-gas.org/index.jsp?stateprov=MO

Map of stations that sell ethanol free gas.

The OEMS will tell you all day long their products are compatible with E10. What is not told is nothing is compatible with the acid like product that is produced after water reaches the saturation point of the ability of the ethanol to absorb the water. What is left is a water alcohol mixture on the bottom of the fuel cell, this is called phase separation. Where is your pick-up in the fuel tank? That's right, your sucking up a nasty weak octane acidic mixture that will deteriorate your fuel system components. I have been through this personally with big boats, with 200 plus gallon fuel tanks. And have seen the gallons of water extracted during a fuel polishing evolution. If you can find it, as the pure fuel website was posted here, use it, you will have MUCH less fuel related problems. Here is a good read if you have not dove into ethanol fuel yet. Read and heed..
http://fuelschool.blogspot.com/2009/02/ ... ended.html
http://fuel-testers.com/expiration_of_ethanol_gas.html

Wow. That Fuel-Testers article says there is nothing that can be added to fuel to stop separation. I guess all of us were fooled into adding Stabil and other additives.

Well, then, the only other thing I can come up with is my home fuel source does not really have any ethanol in their tanks even though the pump has a label indicating 10% ethanol. Maybe the fine print claims "up to" 10%?

My 5 year old generator gas was a little beyond the 90 days expiration.