90 Octane Ethanol Free for SVHO Motor

[gabewhite]

Hello everyone!

I am new here and currently waiting on the arrival of my new 2020 195S (pics to come when it arrives). This forum has already provided me with so much information and hopefully you all can help here as well.
I am considering keeping my boat at a marina with rack service but the highest octane fuel on the river is 90 (ethanol free). I know the SVHO calls for 91 but curious if anyone has had experience running 90. So close to 91 and it’s ethanol free thus having more free energy so maybe this will suffice? I am no expert and this will help decide if I still want to do the rack service or keep the boat on the trailer so I can get 93 from the gas station.

Thanks in advance for any and all help!

 

[anmut]

I would say you're fine. I've never heard of 90 - I'm thinking their sign is old and out of date?

 

[gabewhite]

I would say you're fine. I've never heard of 90 - I'm thinking their sign is old and out of date?

This was my initial thought until I called both places and they confirmed that it was in fact 90. They said they specifically purchase the 90 ethanol free over the 89 with 10% ethanol. In my head I’m thinking why not just purchase 93 lol

 

[Bluewater272]

90 vs 91 isn't about free energy, but resistance to premature ignition. That said, I'd have to imagine 90 is 'close enough' and shouldn't present any problems.

 

[gabewhite]

90 vs 91 isn't about free energy, but resistance to premature ignition. That said, I'd have to imagine 90 is 'close enough' and shouldn't present any problems.

That’s what my gut is telling me but wanted to get some feedback from you all so I appreciate you sharing!

 

[anmut]

I guess I would be interested to know if there is a +/- percentage on what an octane value states on the pump vs. actual in the mix? Meaning if a pump states it's 91, is the refinery allowed to be 90-92 and it's considered valid? Otherwise, most auto engines with octane requirements also are smart enough to retard timing if it senses knock. Unsure if that's true on Yamaha's motors.

 

[marcham]

You could just pour in a can of octane boost with every fill....

 

[EmeryZ28]

I was just about to ask this question. There is a gas station I often hit up right by the boat ramp and it has 90 ethanol free, specifically for boaters as most marine engines dont like ethanol. I ran a tank in my SVHO and it ran great, but I am wondering if I should make it a normal thing or not?

 

[3 green tornados]

I thought ethanol’s down side was that it has a high affinity for moisture. In automobiles it isn’t a big deal because it gets used quickly and won’t absorb enough to damage anything; where as on a boat they are exposed to higher levels of moisture and tend to sit longer. This allows for more moisture in the fuel system which will then corrode because it isn’t flushed often enough.
I run 91 with ethanol during the season and then add VP’s ethanol fuel stabilizer to a very full tank over the “winter.”

Is this a bad idea? Is my understanding wrong?

 

[mrcleanr6]

You are right. Ethanol absorbs moisture and during the boating season its no big deal. Its when they are being stored with ethanol thats a problem. Here in nj, ethanol free is illegal. You cant buy it anywhere in the state so your kinda stuck. My skis I used to drain the tanks in winter and put 3 gal or so of vp c9 which is 94 octane and no ethanol. Boat though would need alot and you cant easily drain the tank. The fuel stabilizer like the one you mentioned and all the others that say they have something like ethanol shield or special treatments for ethanol gas are all just marketing gimmicks. There isnt anything that can be added to gas to keep ethanol from absorbing too much moisture and phasing out. In the winter just make sure your tank is completely full, put stabil in it and it is what it is. Keeping it totally topped off is the best thing you can do.

 

[zipper]

Here in nj, ethanol free is illegal. You cant buy it anywhere in the state so your kinda stuck.

Wow, really? Not even at marina's? All they (marina's) have here is non ethanol gas. I can get it at a couple of pumps here in town. I use it in all our small engines from the weedwacker/chainsaws/mowers on up to the Mercury 15hp OB. I have had to rebuild/replace too many carburators since corn found it's way into gasoline.

 

[mrcleanr6]

Yep nothing. Not even at marinas. Only way you can get it is if its race gas, vp by the pail, etc.

 

[zipper]

Yep nothing. Not even at marinas. Only way you can get it is if its race gas, vp by the pail, etc.

Well that is a bummer. Smells like political payoffs to me. Those people in charge have never had to take apart a carburator on their own and seen the deposits left behind in the needle valve and jets after storage. I like Seafoam, but I don't want to add it in everything if an engine is not run for a couple of months.

 

[mrcleanr6]

yep you pretty much nailed it. typical nj though. there is a rule and regulation for everything here. one day ill retire and get the hell out of here!