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What should I do with old outboard gasoline?

3K views 20 replies 16 participants last post by  TommyV  
#1 ·
Folks: This time of year I often am left with the dilemma of what to do with that last gallon or so of gasoline left in my small outboard gas tank. It is mixed with TCW3 oil at 50:1 and is probably six weeks old by now. I used to dump it in my pickup truck, but I am not sure about that with the TCW3 in the mix. Any suggestions? I would appreciate an environmentally friendly response.
 
#2 ·
By the time you put that in a 16 gallon + gas tank the oil will be so diluted it will not make a difference. Do not know of any other way to get rid of it besides to use it. Been putting mine in the old truck gas tank for years. No problems.
 
#6 ·
What I do is take it to where road construction is going on or other sites and they love old gas for there gas saws or generators or other misc things. I to dont like to dump it in my yard or here some tell me to take a drive and find a home for it. But like I said lot of construction sites that have old equiptment or other things might be a good place. Good luck
 
#12 ·
You have several options. In my opinion here they are in order from most desirable to least.

1. Fill up your outboard tank with 50:1 Gas:TCW3, put some sta-bil in it and use it next spring. This is what I do, it works great. Best to leave it in a place that doesn't see huge fluctuations in temperature, just about any building will do as long as it has 4 walls and a roof. I've put gas like this in an attached garage that stays around 40 degrees in the winter, 80 in the summer, it was fine 18 months later.
2. Put it in the tank for any 4 stroke non-fuel-injected small engine that you will use during the winter (snow blower is a good choice if you have one). It will smoke a little but it will do no harm to the motor, very important to make sure it's NOT fuel injected though. Alternatively, you could put it in a 2 cycle engine as long as it also takes 50:1. I would avoid putting it in any 2 cycle that doesn't take 50:1.
3. Put it in the tank of a any non-diesel non-fuel-injected car or truck (under no circumstances put oiled gas in anything with fuel injection, it could ruin the injectors). It would possibly be safe in a diesel motor but I'd worry about it ruining the glow plugs. In my opinion not worth the risk.
4. Use it to start a bonfire, or several smaller fires.
5. Pour it on the ground to kill weeds (probably rule this one out since you're hoping for an eco-friendly approach).
 
#14 ·
You could also try taking it to a junk yard. They deal with old fluids all the time so they could probably point you in the right direction or might even take it off your hands for ya...
It costs about $4.00 a gallon to re-cycle gas. I doubt they or anyone else wants it.
 
#16 ·
Two words of caution I did not see addressed.
1. Stabil should be added to fresh gas. It will not work on gas that is already old (oxidized).
2. You should not add this gas oil mix to an air cooled engine e.g. snowblower. TCW3 oil is for water cooled engines.
 
#19 ·
On the suggestion of a mechanic, I ran 6 full gallons of REALLY old (about 7 or 8 years old!!) pre-mix through my lawn tractor & it never missed a beat.

Put about 2 gallons @ a time into my 5 gallon tractor can & topped off w/fresh.
 
#20 ·
Two words of caution I did not see addressed.
1. Stabil should be added to fresh gas. It will not work on gas that is already old (oxidized).
2. You should not add this gas oil mix to an air cooled engine e.g. snowblower. TCW3 oil is for water cooled engines.
Thanks for the clarification.

I addressed number 1, I was not clear in my intention though. I put "Fill up your outboard tank..." in my response because he only has a gallon, by filling up the tank, the older gas would be diluted with newer gas and it would safely stabilize until next spring. Stabilizing old gas does not work. Stabilizing old gas when heavily diluted in new gas works fine. It's also worth noting that gas, oil, and stabilizer evaporate at different rates because they don't form a perfect solution. If you stabilize a small amount of gas it won't last as long as a larger amount of gas. By filling up the tank then stabilizing it you eliminate all of these issues.

Pertaining to number 2, putting 50:1 gas and TCW3 in a 4-stroke air cooled small engine is certainly not recommended by any small engine manufacturer. It's not a risk free solution but it has been my experience that it generates no ill effects, it will smoke a little though. Diluting the 50:1 with normal gas mitigates a lot of the risk and the smoke.

Regardless, the best solution is filling up the tank, stabilizing the whole thing, then forgetting about it until spring.