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e85 and performance outboards


RedRocket1647545505

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I was talking to my father the other day about the fuel he runs in his Merc outboard and it got me thinking about what it would take for him to switch to corn. His setup now is wound pretty tight. His Merc outboard(s) are no where near stock, and are pretty much identical to what the pro guys run on their drag boats, so I'm convinced it would be of benefit to him. He's got the fuel system. He has the capability to tune whatever he wants. I can't think of a reason NOT to try it. What are the basics of running corn?

 

Some things I have found:

-Different stoichiometry; requires ~30% more fuel to achieve the desired A/F ratio.

 

-Runs much cooler than gas (a great thing on a 2-stroke outboard which has a long history of melting pistons)

 

-Can be hard/corrosive to different materials. What needs changed out to be compatible? His fuel system is about as basic as you can get, so any changes should be minimal.

 

-Likes to absorb water. I don't think this is as big of an issue as people make it out to be considering people run it everyday in their road vehicles w/o a problem.

 

-He premixes his oil into his fuel tank. Any issues with doing this with corn as opposed to gas?

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Is it an old school 2-stroke or is it direct injected? I'm assuming carb's since he pre-mixes. I would be hesitant to try it in a high dollar motor without some knowledge of how it would do...
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Is it an old school 2-stroke or is it direct injected? I'm assuming carb's since he pre-mixes. I would be hesitant to try it in a high dollar motor without some knowledge of how it would do...

 

Mid 90s blocks. He has several that he tinkers with; 2.4s, 2.5s, 260s, 280s,...

 

They've been converted to EFI (MAD EFI/Brucato system). No direct injection.

 

I tried doing a bit of Google research, but couldn't find much on it. Most stuff just seems to be people repeating what they've heard, rather it be factual or not, who knows. The ODBA guys have probably tried it (they've tried everything), but I highly doubt they post up much of their secrets, so who knows.

 

Right now, he runs the highest pump gas he can find + octane booster + Stabil + oil, and it's still only in the high 90s on the octane rating. I think he could do better if he made the switch; it seems so much simpler to just throw in some 100+ octane and your oil, and be on your way, and cheaper to boot.

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I've got a Yamaha V6 2-stroke in FL...biggest fears in running E85 would be the hygroscopic nature of the fuel: you'd want to make sure to burn off whatever was in the tank within a few weeks of filling it. Plus, I wouldn't know how to tune the EFI or oil injection for additional fuel flow.

 

Short-term gain of a little power? Maybe....long-term damage to fuel lines/engine seals, metal corrosion, complications to other parts of the fuel tank/fuel system? Highly likely. :(

 

YouTube doesn't have anyone running E85 on an outboard. You want to be the first? :)

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I would not run e85 in any marine application. Ethanol and humidity don't mix well. His best bet is to stick to pump gas or maybe try VP race gas if he really needs it. Is this for a pleasure boat?

 

That's why I'm curious about marine applications. If the tank is sealed (minus a vent or two), then how else would moisture accumulate? I would think if you ran the tank low pretty frequently, one would be OK. I'm just looking for an alternate high octane solution for him that doesn't involve $8.00/gal fuel or a degree in chemistry to mix up. Not to mention, it's just different, and I like that.

 

I guess you could say it's a "pleasure boat'', in that, it brings him pleasure. To be specific, it's an Allison XB-2003 (bass/sport/drag) boat. Used for fishing, but also going 100+ in a relatively short amount of time. Also has a nitrous/alcohol injection setup w/ it's own dedicated fuel system/injectors. Any idea how corn plays with the 'other' alcohol?

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I've got a Yamaha V6 2-stroke in FL...biggest fears in running E85 would be the hygroscopic nature of the fuel: you'd want to make sure to burn off whatever was in the tank within a few weeks of filling it. Plus, I wouldn't know how to tune the EFI or oil injection for additional fuel flow.

 

Short-term gain of a little power? Maybe....long-term damage to fuel lines/engine seals, metal corrosion, complications to other parts of the fuel tank/fuel system? Highly likely. :(

 

YouTube doesn't have anyone running E85 on an outboard. You want to be the first? :)

 

No oil injection; it's premixed. And I've heard 30-40% additional fuel required. Other than that, I would assume he would tune it the same way he already does on gas. He's got dual-bank EGTs which he uses quite a bit to try to dial it in.

 

My main reason for looking at it is the cooler running, higher octane (less melted pistons), ability to maybe crank up the compression a little (:masturboy:), and the cheaper price is a nice consideration as well. I'm just trying to weigh the pros and cons of the whole switch.

 

I know some of the pro guys run it in their drag boats, but they aren't leaving fuel stored in them either, which I think would be it's biggest drawback. Good luck on getting those guys to give up their secrets of running it, though.

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Did some digging on this. Sounds like there are pros and cons of normal gas and e85. He would have to do some testing I'm sure. But I guess this guy did it on a standard outboard. Ask your dad if he has any performance parts laying around for my 2.5 200 xri :)

 

http://www.duckworksmagazine.com/06/columns/rob/maib2.htm

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