Gas Tank during the winter-Winterizing

Do most people just use stabilizer, or is draining a good idea? Not even sure how I'd go about draining it but I was curious.

I typically load my tank up with proper amount of Stabilizer and that's that. I recently helped my bro buy a boat and it was still winterized and the boat's gas tank was drained for the winter.

For those that just use Stabilizer, do you recommend filling the tank all the way up leaving less room for condensation, or do you just leave it on the low side so you can use fresh gas in the next season?

Sad that I'm already thinking of winterizing, the season flew by.

Re: Gas Tank during the winter-Winterizing

Most fill the tank to 90 percent to allow for expansion and add stablizer

Re: Gas Tank during the winter-Winterizing

This is a much discussed topic with no right or wrong answer! Merc recommend draining the tank but few people do that. Filling the tank is ok providing you will be using that gas within the next 9 months ( I recently had to drain my tank - gas was old and I haven't used the boat much this year). I don't think condensation is an issue for us folk further north - winter air is very dry.
I will now just add stabilizer to whatever is in the tank, then use that up next season BEFORE I put in fresh fuel.

Re: Gas Tank during the winter-Winterizing

Another retired guy said:

This is a much discussed topic with no right or wrong answer! Merc recommend draining the tank but few people do that. Filling the tank is ok providing you will be using that gas within the next 9 months ( I recently had to drain my tank - gas was old and I haven't used the boat much this year). I don't think condensation is an issue for us folk further north - winter air is very dry.
I will now just add stabilizer to whatever is in the tank, then use that up next season BEFORE I put in fresh fuel.

Click to expand...

They may be no right or wrong answer but there's a LOT of misinformation.

I do not use "stabilizer" or any other snake oil at all. Never have. I also don't store my boat with the tank full or even half full. Never have.

I do put it in the "garage" at approx 1/4 or less in the fuel tank in Aug or Sep (like right now)

In JUN of next year or so, I'll take the boat over to the gas station and fill it up. It'll take approx 30 gallons to fill it.


That's it.

In all the years of storing fuel tanks in boats and planes, I have NEVER been able to detect water from condensation in a fuel tank.

I also ran across the following article from someone who found the same thing.

Water in vehicle (boat) fuel tanks doesn't appear to come from "condensation" at all

The Myth of Condensation in Fuel Tanks by David Pascoe: Boat Maintenance, Repairs and Troubleshooting

The biggest problem in automotive gasolines from long term storage is from higher-end (& more volatile) hydrocarbons evaporating out of the mixture which will reduce the total vapor pressure. low vapor pressure will result in harder starting for carbureted engines. The over all octane of the mixture also degrades with time too mostly because of the loss of those "higher-ends".

NO amount of Stabil, Sea Snot, Owl juice or other BS snake oils can prevent this. (they do improve the bottom line of the retailers though)

The only way to prevent higher end hydrocarbons from evaporating out is to pressurize the fuel tank to at or above the vapor pressure of those components. Then they cannot escape. This is why older gas in most newer cars isn't a problem. cars have had closed systems for many years.

The best way to ensure good fuel for the next summer is to pour it in there before you go boating.

To do that, store the boat with as little fuel in it as practicable, then fill it up next summer. I have found 1/4 tank or less seems to be adequate. I have gone as long as 2 years doing this with no ill effects.

ymmv

Rick