Fuel winterization question

tonystoy

It’s getting down to the last 3 to 4 weeks before I put her away for the year. My fuel tanks are almost at empty. My question is, what’s the best way to store it over the winter?… Fill tanks completely full, half or near empty?
I will be using fuel stabilizer either way. 

Thanks!

Handymans342

Most of us fill up the tanks to prevent condensation but don’t fill 100%. Leave room for thermal expansion in the spring. 

LaRea

In general, it's best to fill the tanks.  Temperature variations can cause the tanks to "breathe" humid air into the tanks [and condense, as Handy said].  The less air in the tanks, the better.  

However, that's not what I do.  For my boat, winter layup is short and fuel never stays in the tank for very long.  It's usually around 4 months from my last fill of the season to the first fill of the next season.  I don't bother adjusting the tank level ... whatever's there is where it stays over the winter.

For people lucky enough to have indoor storage, sometimes the building owner will want tanks almost empty for fire safety.  

Liberty44140

I am completely opposite. I’ve always kept the tanks low, under 1/4, to keep weight off the boat on stands all winter. Never had an issue. 

reneechris14

Yup I do 80% and plenty of Startron,  I also agree with @Liberty44140 its a lot of stress 1500#  on the hull will hot and cold going on. But it has been many years on 80% and have never had water in the fuel, I also change filters after 1st run in the spring.

PickleRick

I also really like the marine stabil.  Academy sports has it the cheapest I've found. 

I like filling up with with high test, run it long enough to circulate into the entire system and then store it.  


Also freeze protection coverage from ski safe insurance is very cheap.

Dream_Inn

I fill mine and usually take her out for one more spin to lower that gas just a tad.  I also add double the startron for winter.  Filters changed in spring after empty first tank.  Been doing it for 20+ years now.