Winter boat storage. Full tank of gas?

Just got a new Alumacraft 175 competitor and it has a big gas tank. 34 gallons I believe. I won’t go through 34 gallons of gas in a summer with my 75 yamaha. Wondering what the majority of people do for winter storage. Gas tank full or near empty. I was leaning towards filling it up and siphon half of it out to put in a vehicle in the spring. Or would I be fine with a quarter tank? I treat all my fuel with sea foam marine all summer. I dont want fuel to be sitting in the tank for over a year if I dont burn through it in the summer.

I have the same boat only 2016. Ive always been frustrated with the fact that seemingly you can call 10 marinas with 1 question and get 10 different answers but when i asked this same question the most consistent answer i got was empty tank for winter storage. In the old days when the tanks were metal they would rust if you didn’t fill it up. now they are made out of plastic so that is not an issue so they have told me to empty it for storage. The marina i store my boat at will pump any old gas out before storage for a charge of course.

Yeah, there’s 20 ways to skin s cat. People do both and it seems to work for both parties. I like fresh gas so I usually keep it near empty.

Is it all non-oxy?

If it isn’t, make damn sure it’s treated and you have a water separator. And I would prefer empty if possible. The more ethanol in your tank will absorb more water.

If it is non-oxy, it’s probably best to treat and and not worry about the level.

gator800r wrote:

Just got a new Alumacraft 175 competitor and it has a big gas tank. 34 gallons I believe. I won’t go through 34 gallons of gas in a summer with my 75 yamaha.

Simple answer to that is; USE your boat more!!

ClownColor wrote:

People do both and it seems to work for both parties. I like fresh gas so I usually keep it near empty.

I agree, buy a good grade of fuel and don’t give it another thought.

Huntindave wrote:

I agree, buy a good grade of fuel and don’t give it another thought.

Or better yet, just use ethanol free premium. Then you don’t ever have to worry about ethanol sitting in there causing problems.

I have the same problem that I have had the same gas for 3 YEARS now. I just treat it every winter when I store and it seems to be working. I used to run it out every year, but now I don’t bother.

I’ve always went with the Full tank method myself. Non-oxy with a good dose fuel treatment. The more open tank space the more room for condensation and thus more water in tank ( just my thinking ) I also like having a full tank of gas to start off the new season with the following winter.

fishthumper wrote:

I’ve always went with the Full tank method myself. Non-oxy with a good dose fuel treatment. The more open tank space the more room for condensation and thus more water in tank ( just my thinking ) I also like having a full tank of gas to start off the new season with the following winter.

X2

fishthumper wrote:

I’ve always went with the Full tank method myself. Non-oxy with a good dose fuel treatment. The more open tank space the more room for condensation and thus more water in tank ( just my thinking ) I also like having a full tank of gas to start off the new season with the following winter.

^

^I do this same thing. Granted, my off-season is regularly only 2 or 3 months and I’m on the water probably 80 days a year. If your boat sits from late September to May, I’d be more meticulous about what I did.

I try to run the tank down to empty or close on one of my last outings. Then, I top the tank to the neck with Premium Non-Oxy and treat the fuel before it goes into “storage” (which is just in the garage where it always sits). I’m of the same logic that the more open tank space, the more likely you could get condensation. There’s a million different ways to likely do this, but the biggest “NO-NO” to me would be storing a boat with regular unleaded fuel that isn’t run very often. If a boat is stored out in the most extreme temperatures this may be more crucial with how the fuel is handled. My boat is in an insulated attached garage that stays 30-45 degrees all Winter regardless of temperature outside. I’ve never had an issue whatsoever come Spring.

Our local marine shop recommends 3/4 full to allow for expansion.

Mine is between half and a quarter I treat it with Seafoam. Then in spring I’ll top it off with fresh gas and good to go. I also drain the fuel rail in the Honda motor as part of winterizing. I get about a cup of fuel out the rail system. All my toys get the non ethanol premium.

I should have mentioned that I have run nothing but premium ethanol free gas in the outboard along with treating every bit of gas that has been in the boat.

Huntindave wrote:

Simple answer to that is; USE your boat more!!

I would love to but having 3 kids under the age of 14 that are heavily involved in sports tends to limit your time on the water. Also the fact of the matter is I don’t run the outboard very much. My trolling motor gets the majority of the run time.

The comments about condensation are the reason that I go with a full tank.

Full tank of non-oxy premium, ethanol free with treatment. Been fine for me thus far.

Seems quite a few recommend premium non oxy…why premium?

Have always gone full tank and has worked well. Regarding why premium. I only put premium non ethanol or non oxy whichever it’s called. I haven’t seen non ethanol that isn’t premium around these parts.

If it’s non-oxy gas, there is no need for extra treatments.

THE reason for all of the premium non-oxy comments is it is hard to find 87 in non-oxy.
DT

regardless if its premium,oxy,non oxy of any octane,gas these days only has a storage life of thirty to ninety days in perfect storage conditions,does anyone here store fuel perfectly??
ie,sealed one way vented container stored out of sunlight,constant temps,humidity,etc.
full tank ,doesnt matter what its made of will condense moisture if anything but full, a good stabilizer,lucas marine fuel treatment,star tron,what ever you feel good about using will help.

concerning any treatment of any kind for fuels we use today,use only as directed as too much can and will do more harm than too little of it.

thank goodness our motors are so forgiving !!,well,at least with some care that is.

Doesn’t matter full or not. I store mine full and have been using sta-bil marine at every fill up as recommended. The fuller the tank, the less condensation they say but living in a cold climate like MN, it really don’t matter. Got a buddy that does nothing but regular gas and a can of seafoam once in a while and hasn’t had a problem in 20 years. Don’t overthink it.

Those tank issues with condensation are mostly related to large vessels that have 100gallon+ fuel tanks. Alot more fuel and room for issues to arise.

Non oxy and your stabilizer of choice will suffice just fine for our Midwestern fishing boats.

All gas goes bad over time. Fuel treatments help a lot. How you store your boat will matter. Condensation can be a factor.
Before I store my boat I run as much out of the tank as possible which is fairly difficult to gauge as my fuel gage isn’t the most accurate. Before I pull out of the water and have it trailered I disconnect the fuel line and run the motor dry. I add a little Stabil and trailer it home which mixes the Stabil in. I store for around 5 months. Fill up with new gas for the new season and haven’t had any issue yet. I’ve done this for 30+ years.

Hard to find a place that will dispose of gas-I have a station by my house that will dispose of a few gallons but they grumble a bit. As others have said even non-oxy should be treated, I usually have a little old (treateated non-oxy) and I top off with fresh in the spring. Last motor had carbs, no problems with this approach for a number of years.

tim hurley wrote:

Hard to find a place that will dispose of gas-I have a station by my house that will dispose of a few gallons but they grumble a bit. As others have said even non-oxy should be treated, I usually have a little old (treateated non-oxy) and I top off with fresh in the spring. Last motor had carbs, no problems with this approach for a number of years.

Anoka county will dispose gas free of charge as long as you’re a resident. https://www.anokacounty.us/DocumentCenter/View/14393/HHW-facility-tri-fold-brochure?bidId=

Other counties may as well.

Truck disposes gas good, tractor, starting the bonfire…

Full tank to prevent condensation, always non ethanol, used to use Seafoam on the last tank and thru the motors.
This year am trying marine Star Tron, as it treats more gallons for the price.

Keep in mind, these are vented tanks, and there will be evaporation of fuel as well. So money gone in the wind. Had a buddy leave his boat in storage for 5 years, person reasons, and he always stores with a full tank, when he took it out this year, it had less than a gallon of fuel in the tank. But, it does evaporate more in heat, so in a hot barn for 5 years of summers, probably helped with that evaporation.

I’ve filled mine with non oxi and forgotten about it each winter for the last 3 winters. Haven’t had any issues.

I think people worry too much about this. Full, empty, half full, whatever. It’s only a matter of 5-6 months max. Even regular pump gas with ethanol will last 6 months no problem.

The problem really isn’t with the gas itself, it’s with guys not using their boats and today with everything getting bigger and bigger, that’s more and more fuel that’s sitting in tanks going bad. Use your boats and run the tanks down as low as possible before refilling. You’ll never have an issue.

Grouse