View Full Version : What do you do about bad gas left over from winter?

05-25-2011, 01:14 PM
Seems like a simple answer, but I wasn't able to find an answer. I have a buddy who is looking to buy a 2002 Supra Launch SSV. We went up to look at it and it looked to be in tip top condition except that the owner had said he did forget to put Stabil in his gas tank which was a little less than half way full during winterization.

Basically this guy said he would have to add the stabil and some antifreeze to get rid of the water if any was in there and then fill it up with new gas and it should run fine. I was thinking that he would at least have to drain the engine and put new gas in. If this boat was fuel injected (I have no idea) wouldn't adding new gas to old be a bad idea? I would think this would only be possible with a carb engine. Besides, what kind of damage would we be doing to the fuel filter etc by running this bag gas?? And finally, if we were to siphon the gas out of the old boat, it seems to me that taking that much gas out is going to be a freaking chore and should be done by the current owner not my friend. It is a red flag to me, bc it seems like this guy has taken VERY good care of his boat from cosmetically and he is an engine guy, so he went over what he does during winterization in detail and it all checked out. Whichever way we do it, I INSISTED to my buddy that he would have to do it and run it before it was bought.

I have always added Stabil during winterization and have had never had a gas problem, so I am a bit clueless.

The owner said if my buddy wanted to empty the tank then fill it up he would have to pay for it or do it himself.

So my question is simply how would you guys handle this situation?

If the boat is indeed fine, then this is a killer deal for him.

05-25-2011, 01:30 PM
so if you empty and fill with new gas and it doesnt check out(test drive) the guy isnt going to reimburse you for the fuel? sounds shady...

I would prefer to drain and fill myself, I wouldnt trust the guy would actually do it... Maybe just put in a few gallons if it doesnt run right your only out a few bucks...

05-25-2011, 01:35 PM
We actually need to clarify that part with him.

He told my buddy, I was standing right there that he did not have the tools or time to drain the entire tank, and was confident that he cold "refresh the gas" and it run perfectly. So he said if we wanted that done, it would have to be on our own dime. So, I doubt he was expecting us to fill it up, or if he was, he is sadly mistaken!!

To me, it seems like you would do this if you wanted your boat sold. I don't feel like my buddy (and myself more than likely) should be siphoning however many gallons of gas is in there period. Where in the heck would I even put it?? :confused:

Can gas be refreshed like he is talking about? It seems like it would have the potential of messing some things up.

05-25-2011, 01:45 PM
To me, it seems like you would do this if you wanted your boat sold. I don't feel like my buddy (and myself more than likely) should be siphoning however many gallons of gas is in there period. Where in the heck would I even put it?? :confused:

Can gas be refreshed like he is talking about? It seems like it would have the potential of messing some things up.

I agree if he wanted it sold he should get her done... Its not a guarantee that the gas is bad, but if it is you cant refresh it... and if there is water in the tank your not going to get it all out by siphoning. You would need to pull the tank to completely empty it.

I would think you should be alright as is, if it just sat for one winter with the gas I am sure its ok. I have gotten away with skipping the gas treatments in the past on a couple of boats and jetskiis.. I always run it as empty as I can then refill with fresh gas...

05-25-2011, 01:46 PM
I'd show up with about 5 empty 6 gallon cans, drain the boats fuel tank into the gas cans and then add about 10-15 gallons gas. Take the boat for a spin and if it doesnt pass that test or a deal cant be made right there on the spot with the boat going home with me I would then empty that good gas I just put into the boat into my truck, put his old gas back in the boat and be on my way. Little work, but I would not be leaving good gas with him.

05-25-2011, 02:08 PM
ditto what moombadaze stated, only I would only put in around 5-7gallons. run it. if it's sold, then take it, if not, dump the bad gas back into the boat and tell him to have fun. keeps you from having to siphon the gas again and you will only be out $20-30 for 5-7 gallons.

05-25-2011, 02:15 PM
I would think adding stabil and some isopropyl and filling it up ( sellers cost) in order to take it for a test run would do the trick. If it works then pay him the 50 bucks for the gas, if not then there is bigger problems and i would pass...

05-25-2011, 02:20 PM
David (my friend) called the guy and he told him that if we wanted to do that, he had no problem with it at all. But he said he thought it was a waste of our time and that gas "could definitely be refreshed to a point where it would be fine to run through the engine until new gas could be put in".

Simply bc I think it is going to be a pain for us to empty all this gas into the boat, any more opinions on whether gas can actually be "refreshed?"

05-25-2011, 02:24 PM
any more opinions on whether gas can actually be "refreshed?"

Never heard of that before--"refreshed"

05-25-2011, 02:27 PM
By adding more gas you would be dilluting possible bad gas not refreshing it.. no such thing...

05-25-2011, 02:31 PM
By adding more gas you would be dilluting possible bad gas not refreshing it.. no such thing...

That is what I said to the guy! He told us that a portion of anti freeze and Stabil would get out the condensation to a point that it would not be a problem. He said he would even pull some gas out of there to show us it had not gelled after sitting in the tank since the end of November.

From what I have read, gas will gel if has been sitting for quite a while and that gas will definitely not run an engine.

05-25-2011, 02:47 PM
I'm not sure about fuel injection but my carbed engine each Spring I remove the gas connection after the fuel pump, connect 12 volts to the pump and pump the gas into a gas can. You want to drain the gas first and I would recommend adding Sea Foam to fresh gas and that will clean the system. I would think about five gallons (1 hr) of treated gas would be enough.

05-25-2011, 02:58 PM
You can't refresh gas that I know of but I don't think it will harm anything fueling it rite up with fresh gas and stabil. Also having a full tank during storage means u would have less potential for moisture in the fuel as there would be more surface area that moisture can condense onwith a half tank as aposed to a full tank.

05-25-2011, 03:13 PM
So... I'm confused. Did you crank her and run it around the lake? It may run fine with the gas in it, as is.

05-25-2011, 03:19 PM
Thats the thing, I am not sure if that boat is fuel injected or carbed. Seemed to me that running bad gas in a fuel injected engine would be worse than if it was a carbed engine.

We didn't run it as it was, but may decide to do that first and if there are any problems then we can go from there.

I think we are going to try and drive up there tomorrow depending on our work schedules.

05-25-2011, 03:26 PM
Buy a bottle a Heet and bottle of Stabil and dump it in before towing to the ramp - if it doesn't run right, I'd take my $10 loss and head home to scour Craigslist some more.

Just my 2xPenny

05-25-2011, 04:09 PM
I own an atv dealership and we have fuel sit in fuel injected units all the time for any number of months, top it up and run it. Stick your nose in the gas cap you will know if it is bad but it will take alot longer than a winter for fuel to be bad. Find out if it was stored indoors or outdoors to see if it has seen extreme temp changes? If inside all year there should be little to no condensation

05-25-2011, 04:29 PM
Thanks for all the replies guys.

The guy has it sitting outside in South Carolina. It is sitting under a carport on asphalt.

I would imagine they got the same freeze we did her ein Georgia. It was in between 35-25 for about a week straight with 4-5 days staying slightly below freezing.

What should we smell for? :confused:

05-25-2011, 05:05 PM
It takes a fair amount of time for gas to go bad. I would go with the stabil and water remover addative and see how she runs. The gas is probably ok. I have forgotten stabil several times and let the boat sit for 6-7 months, topped it off and had no issues. If it has been in there for more than a year, then I would start to worry.

05-25-2011, 05:35 PM
If the guy is an engine guy how come you don't know if its fuel injected or not. An engine may idle fine on old gas but once you open it up then all the unburnt gas will build up in the cylinder coating the plugs and stall the engine. The worse part of not adding stabil is the guming or varnish build up in small passages, injectors as the fuel evapourates..... 5 months , run the thing and if it runs fine and all checks out dump the gas after you buy it...another.02

05-27-2011, 09:11 AM
I think your making way more out of this then needed.

Gas doesnt go bad after 6 months. It loses octane rating and can collect water. I have had multiple muscle cars carbed, and fuel injuected that sat for months and months and then i started them up and drive them around. Sure they dont have the same get up and go untill i burn that old fuel off but they run fine none the less.

Take some water conditioner for fuel, take some octane booster for fuel. Add those both fire that bish up and drive her like you stole her.

To refresh gas by adding more fuel what your really doing is taking a low octane fuel < old fuel > which might be 82 octane and adding premium 91 octane and it basically balances out to 85 octaine and this is why people call it refeshing.> Its best to add straight octane booster and be done with it.

05-27-2011, 09:18 AM
^^^ Amen...sermon over!!!

KG's Supra24
05-27-2011, 10:24 AM
Well summarized by MMandley. I think there are many more other things you should be looking/worrying about rather than 6 month old fuel.

Like he said, put it in the water and drive it like you stole it. You will know if its running right.

05-27-2011, 11:43 AM
Good news. I was able to get cut out of the process. :) My buddy found out yesterday that his brother in law was a certified Indmar mechanic until last Spring and is going to ride up there with him to check the boat out.

We decided before hand that he is going to give that boat a run as is and not worry about siphoning etc.

Thanks to "Mikes" on here for all his help by the way. Provided some insight that helped out tremendously.