View Full Version : fuel tank winterization question

10-10-2009, 09:20 AM
It's winterization time for us in the northeast. For many years I have added the Stabil treatment filled up the tank, run the boat for a while to get the lines treated and everything was fine. With today's wonderful ethenol gas has the process changed? I was told that we should be draining the tank. Obviously that would be perfect but impractical. It becomes very difficult when you have a 60+ gallon tank.

Advice and council is welcome. I have a 2000 Maristar with the LT1 engine. Thanks

TX.X-30 fan
10-10-2009, 10:38 AM
bigmac's lawn tractor runs like a top.

10-10-2009, 11:33 AM
I have been draining my tank for years with no ill effects. Siphon boat to container, container to truck. Jack up the boat on one side and siphon to the low corner. The ability of the fuel to suck up water is an issue. When setting carb floats this year, it was interesting to watch the emptied bowl fuel go from clear to slightly opaque in just a few seconds in the spring. There have been reports of the fuel starting to varnish in just three months. I like starting with a fresh load in the spring. Ethanol also eats rubber fuel hoses, how long it takes I don't know, but think of a spongy hose leaking a portion 60 gallons of fuel over the winter, kind of a concern I think. Empty tank, no potential energy.

10-10-2009, 01:19 PM
I would do the opposite. Fill the tank to capacity and add Stabil if you desire. First, filling the tank leaves no room for condensation to form during the temperature swings of the fall and spring. Believe me, you can end up with more water in the fuel tank than you think.
Second, a full tank of fuel is less powerful than an empty tank when it comes to explosions. A small amount of gas and alot of oxygen is alot more dangerous that a full tank with no oxygen.
Lastly, while fuel can start to go stale, it does not deteriorate nearly as rapidly in cold temperatures vs. warm. Volatility drops with temperature.
I always store my boats with full tanks. Oxygenated fuels have been around along time, and any mid 90's and newer boat will have components designed to handle this type of fuel.

10-10-2009, 02:26 PM
Agreed...full is better than empty on all accounts, especially with ethanol. And the ethanol won't attack anything important on any of these trailer boats made in the last decade or so.

Anyway, ethanol will hold a lot more water in suspension than straight gasoline and forestall phase separation far longer.