Storing With or Without Full Gas Tank

If fuel is fresh a month or so there is no need for much concern, for over a couple of months add a bit of fuel stabilizer for peace of mind. Although it is rare we go more than a month, there has been a couple of times we went 3 months without RVing, I was more worried about chassis battery than fuel degradation issues. I do attempt to fill before getting home after a trip, nothing to do with fuel freshness, just to save the hassle before leaving on our next trip.

Water in fuel from condensation is a bit of a myth. Ran the calculations one time on a 200gal tank (in the boat). If every last molecule of water was transferred from the air to the fuel and the air turned over 100% daily due to heating and cooling, it would amount to little more than a few drops over the course of 6 months. The ethanol should easily be able to absorb it without phase separation.

I'm firmly convinced that water in fuel is typically coming in either with the fuel or from some sort of leak. On boats, it's not uncommon for the fuel fill to be on a flat horizontal surface, so if there is a break in the seal, it could dribble in over a long period of time. Less likely with an RV and a vertical surface mount.

I will agree with putting some stabilizer in as fuel does go stale. I also like leaving the truck with only about 1/4 tank, so in the spring once it's started, first thing is to stop by and fill up with fresh fuel.

Aside from the aforementioned prep for a bugout or other emergency, it is not necessary to keep the tank(s) full form a mechanical perspective. As mentioned, if one is worried about moisture a good ole fillup of E10 will handle a little water. Personally, I'd rather treat "a little" good fuel and fill with fresh fuel before use.
I quit filling up the tanks on (everything) during storage periods many years ago.
But I also have several engines that rely heavily on a certain octane for performance or to not burn down, so I apply it to all.

Fill it add stablizer

We always store full even in the season if we are down for a few weeks.

We live in FL, so from May 1 to October 30 we are fueled up, propaned up, and watered up so we would be good to go if we have to bug out quick due to a hurricane.

Al

rookie_rv wrote:
Hello, Rookie RVer here!

It is best to store motor home with full tank of gas to prevent water accumulation when it will sit for a month or more? Of course there’s fuel additive added and engine ran as well as on board generator to get additive throughout the system.

Thank you in advance!

Water not so much (though it's always best)
Emergency use yes
Imagine you store with 1/4 tank.. Power goes out and there is no heat or refrigeration so you decide to move into the RV. Well you still have no power for at 1/4 tank the generator won't.

On the other hand with a full tank you have power for several days.
And if you need to "Bug out" due to natural or other disaster.. you good to go.

Go look up you tube videos of gas tanks stored with ethanol fuel and low levels. I always to to fill up with non ethanols and full tank. To not allow moisture build up, never had a problem six months later starting it

Fulltimers wrote:
Non ethanol fuel (no alcohol) would be ideal, if you can find it.

Why?

Richard

Non ethanol fuel (no alcohol) would be ideal, if you can find it.