I'm sure this question has come up before, but here is my dilemma: I still have about 70-80 gallons left in a 105 gal tank (ocean boat) from last June. I put in fuel stabilizer in the tank back then and had the boat stored. Never had a water-fuel separator filter before, but putting in a racor right now along with a new fuel-injected volvo penta inboard. Should I siphon the old fuel out or keep it and get another additive? Thanks for your advice.
Last season's fuel - still good?
- Thread starter fish_ak
- Start date
My opinion is I would forget using any fuel additive, now or in the future other than red containers of HEET if you suspect water is in the fuel. Heck, I been using the same gas that is about 3 years old in our snow blower and generators.
Modern gasoline is designed with a 12 month shelf life. Never did understand why people would spend money on fuel additives when the gas is supposed to last 12 months, and after that the experts claim you may notice a drop in octane. Just top off the tank and enjoy it.
Modern gasoline is designed with a 12 month shelf life. Never did understand why people would spend money on fuel additives when the gas is supposed to last 12 months, and after that the experts claim you may notice a drop in octane. Just top off the tank and enjoy it.
I'll take it!
I'll take it!
Remember those old Honda ATC 90 three-wheelers, the first three-wheeler invented back in the early 70's? Removed two of them from a junk pile one day, pulled the rope on one and it started. Now, how old do you think the gas was in that thing, considering it was probably parked where in lay a decade after it's birth?
If your boat won't burn last years fuel you got bigger problems then just old fuel!
I'll take it!
Remember those old Honda ATC 90 three-wheelers, the first three-wheeler invented back in the early 70's? Removed two of them from a junk pile one day, pulled the rope on one and it started. Now, how old do you think the gas was in that thing, considering it was probably parked where in lay a decade after it's birth?
If your boat won't burn last years fuel you got bigger problems then just old fuel!
I've never had a problem running old fuel in my boat, or lawnmower, snowblower, chainsaw, etc. You might notice a slight loss of power, but I'd just top off the tank with new fuel and call it good.
The only problems I've seen with old fuel is in two strokes that use castor oil and the gas evaporpates and leaves a varnish of castor oil thet gunks up the carb.
The only problems I've seen with old fuel is in two strokes that use castor oil and the gas evaporpates and leaves a varnish of castor oil thet gunks up the carb.
alaskamokaiman
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The gas is no good you will have to pay hazmat charges to get rid of it big bucks. I will add it to the old gas I have to get rid of and not charge you to dispose of.
I always topped off my Gas and diesel tanks in the fall when I'd put my boats away for the season... this helped reduce the amount of condensation in the tanks.... I always had good racor filters on all my boats, and would start each season off with a new filter element.. No problems... I NEVER used any additives of any kind...
Rod in Wasilla
New member
Just consider yourself lucky that you have 75 gallons of gas you bought at last year's prices.:w00t:
JR2
New member
I have about 100 gallons in my 160 gallon tank, its from 2009. The previous owner put the fuel in and I bought the boat this summer. At first I was kind of bummed about the old fuel... then I got the thinking that this would save me about 400 buck on my first fill up. Going to add a couple cans of red heat, top off the tank, get a couple spare racor filters and run with it.
The only motor I have ever had any problems with old gas in was my snowmachine. For some reason they don't like year old gas. Mine will refuse to start until I poor a couple of gallons of new into them.
The only motor I have ever had any problems with old gas in was my snowmachine. For some reason they don't like year old gas. Mine will refuse to start until I poor a couple of gallons of new into them.
Akgramps
Well-known member
Top off the tank & run it...............!
kuskoblues907
New member
I practice the same standards as Old John; top of before storing and change fuel filters every spring. I agree with "Gramps," top the tank off and go boating!!
I would imagine that the old gas is fine. But if you're concerned about it I wonder if it would not be a good idea to first run the boat on the gas that's currently in the tank to make sure that the gas is good. If the gas is bad and you add good gas to it, then you've ended up with a full tank of bad gas and wasted money. I've always filled my tank in the fall and when I've run the boat in the spring I've never had issues.
The fuel from last season should be fine with the fuel/water filter installed prior to starting the engines. You definitely want the filter on there to eliminate water from the condensation entering your engines.
The way I understand it, there is no definitive answer to storing fuel over the winter. One camp says that storing with a tank as close to empty is best and then add new fuel and additional stabilizer the next spring. The other camp says to store with the tanks full over the winter, reducing the surface area for potential condensation. Regardless, you always want to have a good fuel/water separating filter and to add fuel stabilizer prior to winterization and additionally prior to the first trip after winterization.
One item to note is that when you store your boat over the winter with a full tank you may have fuel coming out of your vents and spilling overboard as the temperatures warm up in the spring from expansion. This would happen if the temperature was lower the last time you filled up the tanks.
The way I understand it, there is no definitive answer to storing fuel over the winter. One camp says that storing with a tank as close to empty is best and then add new fuel and additional stabilizer the next spring. The other camp says to store with the tanks full over the winter, reducing the surface area for potential condensation. Regardless, you always want to have a good fuel/water separating filter and to add fuel stabilizer prior to winterization and additionally prior to the first trip after winterization.
One item to note is that when you store your boat over the winter with a full tank you may have fuel coming out of your vents and spilling overboard as the temperatures warm up in the spring from expansion. This would happen if the temperature was lower the last time you filled up the tanks.
Akgramps
Well-known member
The way I understand it gas will deteriorate faster in a open container and heat will accelerate that process. Ethanol has a shorter life span even yet. Most boat tanks are not sealed like a fuel system on most modern cars, they are vented to the atmosphere.
The real advantage for us in AK is the fact most boats are stored outside in the winter so not subjected to heat. Someone in Florida that parked the boat for 4-6 months with a etahnol fuel could potentially have problems much quicker as the shelf life is shorter.
Growing condensation in less than full tanks is a misnomer as well, do the research and do the math, water in the fuel from condensation is not substantial enough to worry about it. As someone else said if you are commonly finding water in your fuel, you have another problem besides condensation.
So we have it pretty good up here, I myself waste money on fuel stabilizers, they do work and it is a piece of mind, while the fuel may not "go bad" in 6 months time, it will start to loose some of its octane value. I use a stabilizer that has a injector cleaner as well, saving 10 bucks over the course of the year on a 50K toy seems like false economy to me........................IMHO
The real advantage for us in AK is the fact most boats are stored outside in the winter so not subjected to heat. Someone in Florida that parked the boat for 4-6 months with a etahnol fuel could potentially have problems much quicker as the shelf life is shorter.
Growing condensation in less than full tanks is a misnomer as well, do the research and do the math, water in the fuel from condensation is not substantial enough to worry about it. As someone else said if you are commonly finding water in your fuel, you have another problem besides condensation.
So we have it pretty good up here, I myself waste money on fuel stabilizers, they do work and it is a piece of mind, while the fuel may not "go bad" in 6 months time, it will start to loose some of its octane value. I use a stabilizer that has a injector cleaner as well, saving 10 bucks over the course of the year on a 50K toy seems like false economy to me........................IMHO
I try and do the last run or two with what is left after a 150 gal fill up .... next fuel stabilizer for the winter, then put about two thirds of a tank of fresh gas in the boat first time out has worked well for the last 7 years.
If we had ethanol in our fuel here in Alaska I would say yea, you may have a problem, but we don’t. Ethanol is a big problem in the lower 48 especially with outboards because it breaks down quickly and can mess up your fuel system.
I top off my fuel tanks after every trip and before I park it for winter, have never used fuel stabilizers on outboards. On my first trip out I put 2 cans of SeaFoam in each tank to clean things out. After returning I change the oil and Racor fuel filter, boat is good to go for another season. The SeaFoam tends to dirty up the oil with residue like carbon buildup and other deposits from the fuel system, so I figure it makes since to change the oil afterwards.
I top off my fuel tanks after every trip and before I park it for winter, have never used fuel stabilizers on outboards. On my first trip out I put 2 cans of SeaFoam in each tank to clean things out. After returning I change the oil and Racor fuel filter, boat is good to go for another season. The SeaFoam tends to dirty up the oil with residue like carbon buildup and other deposits from the fuel system, so I figure it makes since to change the oil afterwards.
Ak River Rat
New member
I too, like the others, would not worry about it. You could always add Premium or Avgas to top the tank off to bump up the Octane, but doubt if I would spend that much more. Go have fun,
ARR
ARR
Would NOT use 100LL avgas in anything but my plane .... it is loaded with lead, something outboards or marine io or inboard engines are not built to deal with. Lead could cause valves to stick and I think it might screw up the emissions stuff.
