Winterizing with fuel tanks full or empty?

Family knot · **Posted:** Mon Sep 29, 2014 3:34 pm

I had a conversation with a buddy at marina regarding winterizing with fuel tanks full vs "not full"? He's leaning towards not full this year.

I've always gone 7/8 full.

What do you guys do? Pro's/Cons?

LouC · **Posted:** Mon Sep 29, 2014 3:41 pm

Whatever it is when the boat is pulled out, I do always dump the filter out in a mason jar to check for water though.

fi.na.tine · **Posted:** Mon Sep 29, 2014 4:13 pm

I have been told the fuller the better. More gas = less room for water.

TimBobCom · **Joined:** Wed Aug 06, 2014 10:23 am **Posts:** 44

If you have ethanol in your gas tank (E-10 for example) you need to worry about phase separation as well. If this is the case I would rather store nearly empty and just add Sta-Bil for the winter. I had done this many times with my previous boat and never once had an issue with moisture in the tank.

NiagaraChillin · **Posted:** Tue Sep 30, 2014 12:44 am

I've done both, full and almost empty. Just add Sta-Bil. Never had a prob in spring.

weather · **Posted:** Tue Sep 30, 2014 8:40 am

NiagaraChillin wrote:

I've done both, full and almost empty. Just add Sta-Bil. Never had a prob in spring.

Yup, I'll second this.

JeffLW · **Posted:** Tue Sep 30, 2014 8:55 am

I've always stored cars with the tank full. I assumed the boat would be the same, but after talking to a few marine mechanics I store almost empty. They had a few good points.
It is a LOT of fuel/$$$ to leave just sitting there all winter.
If it does somehow go bad then you have a lot more of it to deal with removing in the spring.
If a leak developes over the winter, better to have a 10gal leak out than 80 or 100gal.

This pic always comes to mind when I think about the last one.

Jdpber · **Posted:** Wed Oct 01, 2014 10:27 am

well i always inspect the tanks as best i can.. But I store with a full tank for these reasonings. it is 3-4 months off and that is fine with proper stabal in the fuel. And 2nd if the tank is full their is not air gap to condensate or allow vapor break down or tank sludge to form. A dry tank sitting all winter can create varnish on the tank walls that is ready to clog filters and injectors and carbs the first outing of the season..

Technologic80 · **Posted:** Wed Oct 01, 2014 2:58 pm

Leaving the fuel tank full is Russian roulette to me.... if that gas goes bad, or if you buy bad gas when you fill it up, and it sits all winter- you are stuck with 80-100+ gallons of bad gasoline.

I have "always" stored my tanks 1/8 full of stabilized fresh fuel. My logic is that way, if it becomes stale or is bad gas from the station, I only have 10-15 gallons of it to siphon out or burn.

Never ever had a problem. I have however, helped many boating friends who have bad fuel at the beginning of the season because their treated fuel went "bad" over the winter months, or was bad to start with. :wink:

www.iFourWinns.com

Winterizing with fuel tanks full or empty?

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