Boat Gas Tank

Is it better to keep your boat gas tank full or keep it as low as possible, to store it for winter?

I think as long as you stabilize your fuel, it’s 6 one-way, half-dozen the other.

The theory has always been more air in the tank allows more condensation.

I used to be in the camp of fill the tank at the end of the year, and now have switched my thinking and leave the tank at where ever it is at, and put fresh higher test gas in at the start of season. I do run non ethanol all year with marine Stabil, as as my engine calls for mid grade gas, try to use premium no ethanol at the end of the year. Supposedly gas looses a bit of its octane rating over time, so that is why I do it the way I do now. There seems to be firm beliefs either way, and honestly couldn’t say for sure what way is the best, but defiantly make sure you have some fuel stabilizer in it, and if you can no ethanol.

I used to store everything with the tanks full. Now with plastic gas tanks I don’t think condensation is as much of an issue anymore so I store them at what ever level they are at with treated gas and fill with fresh fuel in the spring.

Stabil instructions on the bottle (red stuff) say 95%full!

That’s probably so they sell more Stabil. 😂

I don’t think it matters. The #1 thing is to cycle through your fuel. If leaving the tank half full helps make sure you burn off that old gas first next year, that is a good thing.

Adding a few gallons of fresh gas on top of 3/4 tank of old gas doesn’t renew the old gas.

Grouse

I always empty mine and put the gas in the mower.

Lund owners manual says completely full or completely empty, they say either way don’t matter with plastic tanks . No explanation for why not half full ?

I fill mine completely before adding Stabil due to the premise of there being less surface area for condensation. I have not had issues nor do I think it’s a big deal to do it differently with today’s plastic tanks. The only thing I do differently in Spring is try and run that first tank fairly low (under 1/4) before adding more.

I don’t run my big motor much because I fish pretty small water at is electric only. Over the past 10 years I have only filled up my tank twice and that was years I knew I was going up to MN for a few weeks and would burn through it. Most years I just Seafoam or Stabil what ever is left in my tank and store it away for winter. I am sure it has never been over half full. I have never had any trouble in the spring starting up. Pretty much starts like every other time when I don’t start my motor for a long time. Takes a few cranks but then it fires up. Once I get it started once, it always fires off. I DO run out my mower, sno blower etc, and used to run out my auger when I had gas. I just don’t have an easy way to do that with my boat and I have not had any problems. I don’t think it is a big deal any more with the plastic tanks.

buckybadger wrote:

I fill mine completely before adding Stabil due to the premise of there being less surface area for condensation. I have not had issues nor do I think it’s a big deal to do it differently with today’s plastic tanks. The only thing I do differently in Spring is try and run that first tank fairly low (under 1/4) before adding more.

X2 – This is how I’ve always done it. I also like that the tank is already full come spring.

My new boat has a 60+ gallon fuel tank. That put a wrinkle in a full tank idea.

I filled my boat tanks and added stabil and some seafoam. Because if biden gets in gas will probably be way more expensive come spring

catnip wrote:

Because if biden gets in gas will probably be way more expensive come spring

If…

Keep clinging to that hope.

Correct me if I’m wrong, but if you only use ethanol-free premium fuel, do you still need to use fuel stabilizer for the winter?

The place that winterizes my outboard always asks me what kind of fuel I use when I drop it off for that service.

gimruis wrote:

Correct me if I’m wrong, but if you only use ethanol-free premium fuel, do you still need to use fuel stabilizer for the winter?

I still would. Gasoline was degrading long before ethanol-blended fuels came to be the norm. You’d likely be fine for the +/- 6 months you store your boat, but Stabil is cheap, why take a chance? You never know what might happen that could leave your boat sitting for longer than planned.

Ralph Wiggum wrote:

I still would. Gasoline was degrading long before ethanol-blended fuels came to be the norm. You’d likely be fine for the +/- 6 months you store your boat, but Stabil is cheap, why take a chance? You never know what can happen that would leave your boat sitting for longer than planned.

Ok thanks will do. You’re right it’s cheap and easy to do.

there are different types of stabil and there use is based on the type of fuel to be treated.