Winterize Fuel Tank-To Fill or Not To Fill

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Nov 21, 2006
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24294
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My boat has a 95 gallon gas tank. Everything I read says fill it 95% full to help prevent condensation. 90 gallons x 6.4Lbs = 576 Lbs. I'm not planning on taking it off the lift this year. I don't have a good feeling about adding that weight to the lift, bunks and hull. What is the option to not filling the tank? I have a Cruisers 2670 with an aluminum tank. I can't find non-ethanol gas anymore.

Thanks
Dave
 
I've stored mine (300 gal) about 1/4 full and well treated with Startron or Stabil for years with zero problems. Never see any water in my fuel water seps either. The wt of 300 gal of fuel on the trailer is an issue for me also.
 
If you can get it completely empty, it's the best way to go, otherwise almost full.
 
Not as big of a deal as most people make out. Your just letting that fuel get old.
 
If you have ethanol in your fuel, it is a VERY BIG deal!!!
 
Unless you can get all the fuel out of the tank, the next best thing is to keep it full and stabilized. With the tank full there is not as much air, which contains moisture, in the tank to cause condensation. Cold winter air contains much less mositure than the air in summer. Based on that, the chances of fuel seperation are greater when the boat sits with a 1/4 tank of gas in the summer versus the winter. Granted, the boat gets additional fuel during the summer unless its not used.
 
Our last 2 boats had either 2-100 gallon tanks or 1-300 gallon tank. All I ever did was stabilize whatever fuel was in the tanks at haul-out and left it that way. We are on the Chesapeake Bay eastern shore in MD where we get some pretty dramatic temp swings and a lot of wet springs. We never had any problem with condensation in our tanks or water in our fuel. The only problem I ever had in the spring was the one year with the first tank of E-10 that was left over the winter. So, IMO experience the whole condensation thing is a non-issue.
 
I put Stabil in my tanks before the last ride so it gets circulated and then I put the boat away with the tanks about 1/4 full. I should mention that I use Startron during the season.
The old wisdom was to fill the tanks before storage to prevent moisture, but that changed with ethanol. The gas with the ethanol in it has a much shorter shelf life so the current theory is that the less gas you have turning bad in the tanks the better. When spring rolls around you get to top off with fresh gas and you're good ro go.
 
I also treat my tanks before the last ride, whatever is left is left, no issues for me.
 
I always have filled my tanks about 90% with stabil, in for the last couple of runs.

This year I did not have time to fill it before I took it to the marina where I store it. I asked the to put $150 in each tank. Thier suggestion was to wait for spring. In thier words " you are much better off leaving the tanks closer to empty, and top off in the spring.

They knew by suggesting that that they would lose the gas sales, as I am out of there long before they put the gas docks in, in the spring. I also do not have any mechanical work done there. (They do good work, but I am to cheap to pay them to do it!)

I can only assume that they have my best interest in mind.
 
This was a hotly debated topic when Ethenol first started making an appearance. Now it seems most folks have settled on how they like to handle it. I have always left my tanks under 1/4 full and used lots of marine fuel stabilizer. I have never had a problem. Ethanol binds with water vapor. The more gas you have in the tank, the more ethenol and the more chance for contamination. Leaving the tank full does not make you immune to this as all tanks are vented to the outside. Also, the less gas in your tank at the end of the season, the less that will be subject to phase separation over the winter. When you add fuel in the spring, it's fresh, not six months old. And finally, if you do have a problem with the fuel in your tank over the winter, in my case getting rid of 20-30 gallons is a lot easier than trying to get rid of 140 gallons.

Having said all of this there are plenty of people on this board that leave their tanks full or partially full and have never had a problem, so you just never know.
 
Good stuff and my thoughts that leaving the tank about 1/4 full would work. I think I'll run the existing fuel filter in the spring when I start off and then change it right away. You can tell you guys are thinking. Thanks! Dave
 
Hey All,

I have a plastic 77 gallon tank in my Martinique.
In the winter, I keep the tank about half full with stabul(read directions for ratios).
In the spring, I just fill it up-no problems!

TJ
 
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