What to do about stale fuel

[poppyjoel]

I have a 33 Grady white Express that I haven't used much during the past two years. The two fuel tanks hold about 350 gallons of fuel. Just about all of the fuel is about two years old, dating back to 2013. The correct amount of Sta-bil was mixed with the fuel as was fuel stabilizer when the fuel tanks were topped off. The boat currently runs well but I'm very concerned about next season, due to the age of the fuel. I have used about 64 gallons of the 150 gallon tank and the same amount from the 200 gallon tank. Is it necessary to run the boat as much as I can to use as much fuel as I can before decommissioning the boat for the Winter (I'm in New Jersey). I'm wandering if I should leave the fuel tanks, with the older fuel, until next Spring when I can top them off with fresh fuel, or should I top them off now? Also, do I need to add more fuel stabilizer?

I'd sure appreciate any help I can get!

Sundance

 

[magicalbill]

If it was me, I'd run out as much of the old fuel as possible, weather/wind permitting before your winter lay-up. Refill to the top with fresh, non-ethanol fuel & the appropriate amount of stabil before you put it to bed.

It shouldn't take long to empty it at 1.1 MPG.

 

[Fishtales]

The key is to use it or get it off the boat.
- I'd run out as much as possible.
- Determine the amount left and make a decision to either have it pumped or mixed with fresh fuel. If 1/3 of the capacity or less, I'd fill and stabilize and plan to run the first tank down as early as possible next year.
- The other option is to have the tanks pumped at the end of the season. If you do this, your choice to fill now or in the spring. Whoever is doing the winterization can most likely handle getting rid of the old fuel.

tx

 

[blindmullet]

I will be doing this on my new grady. I'm using a pump with a filter to take out of one tank and put it in the other going back and forth. My family has a commercial boat that we have had to do this on. Sometimes you get bad fuel from the fuel truck.

 

[Harpoon]

The problem is the octane rating will continue to decrease over time, perhaps to a point where your engines can no longer compensate for it by adjusting timeing or spark advance or whatever those computers do..

I would get as much fuel out as possible, perhaps put it in your vehicle especially if you have a truck that chugs fuel. If you have at least 1/2 of it gone you could top it off with high octane fuel in the spring and be fine.

 

[seasick]

I have a 33 Grady white Express that I haven't used much during the past two years. The two fuel tanks hold about 350 gallons of fuel. Just about all of the fuel is about two years old, dating back to 2013. The correct amount of Sta-bil was mixed with the fuel as was fuel stabilizer when the fuel tanks were topped off. The boat currently runs well but I'm very concerned about next season, due to the age of the fuel. I have used about 64 gallons of the 150 gallon tank and the same amount from the 200 gallon tank. Is it necessary to run the boat as much as I can to use as much fuel as I can before decommissioning the boat for the Winter (I'm in New Jersey). I'm wandering if I should leave the fuel tanks, with the older fuel, until next Spring when I can top them off with fresh fuel, or should I top them off now? Also, do I need to add more fuel stabilizer?

I'd sure appreciate any help I can get!

Sundance

Our experience with long stored boats is that if you drain out a sample and it looks good(no separation, no water) and it smells like gas ( it may not) then it is OK to use Now you may decide that you would prefer to use it in yard tools or an older vehicle instead of your boat If you feel that you need to get rid of it, you can find many folks who would take it if you ask around, especially business with older trucks.
Adding fresh fuel to old fuel does not necessarily make the old fuel newer. Bad gas is bad, period.
As to the comment about octane, it is true that octane can lower over time so to an extent, the issue may be what octane was put in it to start. In addition, some fuels like Valtech have additives that are more gentle on marine motors. I don't recommend topping off the tanks because the gas may go bad and next season you will have wasted another 120 gal of gas. Store the boat, make sure the seals on the fills are in good condition. Do whatever winter prep you would normally do and next season do the gas test I mentioned before starting the motors. If the gas looks and smells OK, test your motors. I usually do not change my fuel filters until after the initial running . If there is crap that's going to clog them, clog the old ones.

 

[Harpoon]

Leave some beer and bait on the boat and I'll be happy to burn the fuel for you !

 

[drbatts]

Run the boat and burn off as much as you can this season. If it was me I would try and burn anything left over off in our cars. Should be fairly easy to unhook fuel line from the engine then using the primer ball and gravity siphon off the rest of the fuel as needed into gas cans. Then start with fresh fuel in the spring. If there is minimal fuel in the tank, you can probably get away with diluting it out with fresh fuel, and be fine. However adding fresh fuel to a significant amount of bad fuel will just result in more bad fuel. Save yourself the headache.

 

[seasick]

Run the boat and burn off as much as you can this season. If it was me I would try and burn anything left over off in our cars. Should be fairly easy to unhook fuel line from the engine then using the primer ball and gravity siphon off the rest of the fuel as needed into gas cans. Then start with fresh fuel in the spring. If there is minimal fuel in the tank, you can probably get away with diluting it out with fresh fuel, and be fine. However adding fresh fuel to a significant amount of bad fuel will just result in more bad fuel. Save yourself the headache.

Assuming the boat has the standard anti-siphon valve, it will not siphon. You either have to pump the primer bulb or use a fuel certified explosion proof fuel pump. Believe me, it is not easy to empty a tank using the fuel line.
We are talking about 220 or so gallons of gas. Even running the motor at speed under load, you will have to run 10 hours or more to burn off the fuel. At idle in the dock, you will run for a whole day or two. It's just not practical.
Besides if the gas is bad, why run it through the motor? If it's good, why waste it?
The question is,"If the gas is still OK will it be next season?" probably...

 

[suzukidave]

i just got some advice from the local bulk fuel business on how to do this. they have a pump out kit they rent out with a line, a fuel safe pump and a miniature gas pump nozzle on the end.

when you pump out the gas, connect the pump after the water separator and primer bulb. drain the water separator before you start and check on it regularly. use the bulb to prime the line then turn on the pump. dispense the gas into jerry cans. they also lend/rent those.

they will take the gas for free but they say it can be used even if it if 4 years old (my situation). i need to run it through a high displacement low compression engine. a farm tractor or a v8 pickup/suv that will not be hauling or towing anything is ideal. for a vehicle start with a 1/4 tank blended 50/50 with the highest octane premium gas you can find with the premium added first. if you run into problems you can experiment with the dilution needed or fill the whole tank with premium to get rid of it. you can also add seafoam and methyl hydrate, which is alcohol that will deal with any water.

if that experiment works ok, the drill is to put half a tank of premium in then add half a tank of old gas, then when you get to a half tank top it up with premium, then next half a tank of bad gas and so on. every second tank add 250ml of methyl hydrate and 1/4 can of seafoam.

i haven't done the math on using it up this way yet but i may just give the gas to my farmer neighbour.

 

[grady23]

Advertise on Craigslist that you have stale fuel available for free. People that have big heaters called Trash Burners use it to mix with oil and othe fossil fuels to burn it to heat large buildings. I got rid od 135 Gal of old fuel that way. A local fuel polishing Co wanted $2.75/ Gal to dispose of it and would probably done the same thing with it.