Mixing Non Ethanol Gasoline and E10

ggray

Seaman
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Jul 1, 2010
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65
I understand that is not a good idea. True??

I have an 18 year old Tohatsu 30 hp 2 stroke that has not been unhappy running on E10 (as long as I keep the gas fresh and stabilized).

But I needed to buy a gallon for reserve, and was non ethanol.

I've kept it separate, didn't need it at the time, and wonder if I should use it now.

Only a gallon so no big deal, but using it is the easiest way to "get rid" of it, if that doesn't cause problems.Can I run one tank dry, run the Non ethanol tank dry, then back to my E10?
 

GA_Boater

Honorary Moderator Emeritus
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False. Throw it in the tank.

I mean when E10 came on the scene we filled up with E0 still in the tank. It isn't like mixing antifreeze types.
 

Sea Rider

Supreme Mariner
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The engine won't know nor complain about which type is being burned...LOL!!

Happy Boating
 

dingbat

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While it’s impossible to find MTBE in on-road gasoline anymore (the gas you get at the pump to put into your car or truck), there are some states like Florida where MTBE gas still hangs around in “off-road” gasoline supplies, such as those used at marinas. They may still use it because they still need to add something to the gas to improve its octane rating. Ethanol would normally be used for this purpose, but boaters hate ethanol, so they used MTBE gas where they can instead.

Because there is still some MTBE gas floating around, you get the inevitable situation where someone, whether an end user or a fuel distributor, adds gas with MTBE to normal gas with ethanol. And that’s where the problem arises.

https://www.bellperformance.com/blog...anol-Don-t-Mix
 
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Scott Danforth

Grumpy Vintage Moderator still playing with boats
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other than E10 having less BTU's than E0, no problem mixing
 

Grub54891

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Drop off the fuel at my place. I know how to dispose of it properly.:D
 

JimS123

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According to the agencies that test and police gas stations, if you buy E10 is could be anywhere between E0 and E15. Or, if you buy E0 you could very well get E10.

Take the reports for what they are worth. I dunno if its true or not. In any event, the naysayers may very well be getting alcohol at times and don't even know it.
 

ggray

Seaman
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Jul 1, 2010
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Thanks! I will dispose of usefully!
It must have been the MTBE issue that I remember reading about.
 

Sea Rider

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Tohatsu engines won't care, our fuels are now E8. Runs with no problems at all. Factory specs specifies max E10 contents use, more will surely have side effects...

For your peace of mind run carb dry after each use, E fuels tends to balloon up much faster diaphragams inside fuel pump when engine is shut off and fuel remains inside pump than non E fuels

BTW, there's not such thing as newer OEM diaphragams are made to hold much better E fuel punishment, that's a tech fallacy as will balloon way faster according to my experience using non E and E fuels on many Tohatsu different HP-OB's over time.

Happt Boating
 

Sea Rider

Supreme Mariner
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That's nothing new. Grandpa always said to run OB's dry after use. I've been doing it for 55 years now.

Touche, but probaly OP has never done that, he's the only one that can tell us if he runs fuel dry or leaves E fuel sitting inside carb-fuel pump. As always, there's pros and cons conflictive answers about such practice..

Happy Boating
 

hemi rt

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Jul 1, 2010
Messages
321
People have a misconception of how fuel is made, E10 fuel is not refined as E10; the ethanol is added to the transport tank just prior to the regular fuel (non ethanol fuel ) being put in the transport tank. Fuel is ordered by the Gallon (Litre in Canada) and the driver has a chart that shows how much ethanol he needs for a certain amount of fuel. I have seen E10 actually be E15 as the driver got too much ethanol prior to adding the regular fuel. The refinery does not premix the gas with ethanol.

Just like when you buy mid grade fuel you are getting 50% E10 and 50% high octane (86 mixed with 90) gives you 88 octane, that is if the pumps are working perfectly; which in most cases they are not so you may be buying fuel closer to 86 or 90 depending on which pump at the storage tank is stronger. so, hopefully when buying 88 or 89 grade fuel you are getting less ethanol then buying regular fuel as the pumps above ground are called blend pumps and 99% of service stations only have storage tanks for holding regular (E10) and high Octane (90) which is usually ethanol free.
 
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Scott Danforth

Grumpy Vintage Moderator still playing with boats
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and some fuel stations in Alabama had as high as 30% ethanol at the pumps. small engines were failing left and right. I believe there was a class action suit against the fuel distribution network.

however back to the OP's original question. no problem mixing E0 and E10
 

aimlow

Petty Officer 2nd Class
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Nov 7, 2018
Messages
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MTBE and ethanol are both "oxygenators". Ethanol is also an octane improver. Rec90 is just 93 octane E10 without the ethanol. The only "gasoline" which is much different from pump gas in Avgas.
 

JimS123

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Ya got yur Regular, Ethyl and now Unleaded. Doesn't the "E" stuff have to do with internet letters?
 
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