Ryan,

The guy that used to do all my dad's boat work, and subsequently mine, until he got out of it, told me to leave it completely full, so there was no air to collect water vapor. I discovered that was a problem, due to expansion forcing fuel out of the vent (it was very low on our Rinker). Then someone else suggested leaving enough for that expansion. I used to do that, and didn't have much of an issue. Others have told me to completely empty the tank, them completely fill it at the start of the season and run that tank out as much as possible before filling up again. I now try and leave the tanks as empty as I can over the winter, but I keep the boat in my shop, which is relatively temperature stable. I do fill it up pretty much full at the beginning of the season, then run it out before refueling again, however.

I have always been under the impression that it was water vapor finding its way into the fuel in the tank. A full tank doesn't allow any air to carry in said water vapor. and empty tank won't have any fuel to absorb said water vapor. A little fuel will only absorb so much, and can then be diluted pretty well fill with a complete fill-up. The various explanations all make sense for different reasons.

I don't ever recall hearing about fuel gelling unless it was allowed to set for a really long time. Not saying it won't, just that I'm never heard mention of it, nor have I ever seen it happen with either of our boats within one off-season.

Thanks. Brad.

been too cold here still

Gasoline loses octane the longer it sits. From all my summer/winter toys and letting vehicles sit, I learned to keep as little in tank as possible for storage. Turn off any fuel petcocks you may have. If your storage time turns into an extended period and you did not properly drain the entire system the gasoline will become un-burnable crap with horrible smell. With less gas in the tank it's easier to drain in that case. If your boat sits for a few months, the gas will probably burn, but not correctly. In that case, having less gas leaves you room to ad lots of fresh gas. Storage also gives sediment time to get to the bottom of the tank and pickup and will help quickly clog filters. Always clean/change them after storage after running the engine awhile to help get rid of that stuff. Never hear of gasoline gelling, only diesel.

That is my route. Burn every drop possible in fall and refill w fresh in spring. Ran out with the Seadoo a couple times