Gas and Ethanol

BananaMan

Cadet
Joined
Jul 24, 2023
Messages
16
Hey Everyone,

I recently bought myself a new Tohatsu 9.8 outboard. A nice little upgrade from my 1975 6hp Evinrude. (which I still love)

I live up in Canada and all of our gas is now at least E10.

My outboard motors only get about a month or 2 of use each year and I have been stressing about the issues this could potentially cause on my new motor. So much so that it has lead me down a youtube rabbit hole on how to separate ethanol from fuel. I don't really want to do this as my boating time each year is already limited. However, I don't want to have issue with my motor either.

My plan is to essential run the carb dry and drain it before long term storage.

I never use old gas. If I have some in my Jerry can before the season I will empty it out and use it as a fire starter. I am always filling up with the highest octane possible (usually Shell V power as its the closest to me).

A few questions for you.

I have always been told to run premium/highest octane available for small engines. Is this still the case even with E10 fuels?

I plan to add a stabilizer each time I fill up my outboard tank, Is there a specific one you would recommend? (there are so many to choose from)

Thanks
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,548
your new motor was designed to run on E10, not E15

youre fine running it on normal pump swill

no need to spend more money on higher octane

since you only use the motor for a few months, no need for a stabilizer
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,655
If you run the carb dry you won’t likely have problems. I have used Stabil or Marine Stabil not sure that it’s necessary but I’ve done that for years. I’ve have used fuel up to 2 years old without problems in the boat (4.3 Quadrajet) or any of the 8 small engines that I maintain including 4 & 2 stroke engines. Carbs with bowls I drain the bowl; 2 strokes with the little cube carbs I start them 1x a month unless it won’t be used except in an emergency like the chain saw in that case I run it out of fuel & drain it.
With bowl type carbs I have had less issues after I started draining them. The only one I don’t do that with is my back up generator which I start once a month.
 

MattFL

Master Chief Petty Officer
Joined
Oct 20, 2010
Messages
856
Don't bother trying to remove the ethanol from gas, it's not worth the effort. Your motor will run OK on the ethanol, it's just not good for storage. Stabil brand stabilizer seems to work good for me. My little Tohatsu 6HP only gets used a couple of times a year. All I do is drain the carb when I'm done. If your carb has a drain plug, draining is better than trying to run it dry, it will stall before the carb is 100% empty. If I know for sure that it's going to sit for some time, I'll fog it (Stabil fogging spray works great). Don't be shy with the fogging oil, it will smoke like the end of the world but coats the insides of the cylinder to keep it from rusting. The pilot jet on this carburetor is right on top, easy access so I'll put some fogging oil in there too. It stores perfectly this way, no problem the next time I go to use it.
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,081
Most E10 fears are from folks that don't follow simple instructions, as mentioned, drain excess fuel out of your motor and use fresh fuel each time and you will be fine...
 

FLATHEAD

Captain
Joined
Dec 29, 2002
Messages
3,165
I’ve used stabil for years on boats and motorcycles before winter storage. Never an issue at spring start up and running when the good weather gets here. We now have a gas station nearby that sells ethanol free gas. I use it in the boat.
 

cyclops222

Lieutenant
Joined
Mar 21, 2024
Messages
1,294
Since you run everything DRY before storage ? You do not need to use any additives. E-10 gasoline has a HIGH Octane in every gallon.
But in my auto engines I do get Carbon Build up in the engines over a 2 month period. So I sometimes add a can of Seafoam engine tune up To remove the carbon.. That adds about 12 % of lost mileage back.. The boat engines It is just a habit I have acquired. I run older 2 stroke outboards.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,655
I use Stabil in my E10 gas and drain all my yard machines that have bowls on the carbs. The small 2 stroke machines with the cube carbs I just start them once a month; unless they are hardly used like the chain saw then I run them out of gas & drain. I added shut offs on the machines that have bowl type carbs to make it easier.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,548
I leave 2-stroke oil in the saws, etc for months between use.
2-stroke oil is a much better stabilizer than stabil
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
12,655
The only exception to draining that I thought of is the older style Briggs mower engines with the carb on top of the metal tank. On these if you run them out of fuel the tank starts to rust inside, so it is better actually to keep these full for storage. I have one of them with the Pulsa-jet carb.
 
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