Fuel stored over winter and leaked

Before winter I put some fuel stabilizer in a full 6 gallon simple plastic fuel tank and set it in the back of the boat. I did not vent the tank because I was concerned about evaporation. Unfortunately, when the weather started to warm up the pressure in the tank pushed fuel (mixed with oil) around the threaded fitting where the hose connects. Very disappointed when I took the cover off this spring to find that there was oily fuel in the bottom of my boat - especially so since I need to repaint part of the floor. Anyway...

A couple of questions:

1) Should I have stored that tank with the vent open?

2) Can I expect that the fuel and oil remained thoroughly mixed or might what remains in the tank no longer be the proper ratio?

Thanks.

Re: Fuel stored over winter and leaked

I always leave a fuel tank with the vent just cracked open, so if the sunlight heats it up, it won't swell up and burst or leak. Very little evaporation through a small vent and your gas and oil is still mixed fine and should be ready to go. Oil/gas ratio is not all that critical anyway. Good Luck!

Re: Fuel stored over winter and leaked

I never use mixed gas that is more than a couple months old personally.... On my 2 strokes, I run em dry before winter..... spray your floor and bilge down with foamy engine bright or simple green and take it to the car wash.... it'll be fine..... tighten up that fitting because it'll be an air leak for you while running

Re: Fuel stored over winter and leaked

Thanks for your responses, guys. I definitely wouldn't use this fuel if I had not added fuel stabilizer (Sta-Bil). I think that stuff does a good job, though, and I burn the stored winter fuel in both my mower and motorcycle in the spring. No problems with either.

On the air leak and venting issue, do I want that vent tightened down while running? I'm brand new to boating...sort of. I'm restoring the boat that belonged to my grandparents when I was a kid and have rebuilt an old Evinrude as well. Hoping to get them out on the water next week for their first test.

Thanks again!

Re: Fuel stored over winter and leaked

Question you should have asked was "Should I store gas cans on the floor of my boat". Leave the thing on the garage floor next year.

Re: Fuel stored over winter and leaked

Your air vent must be open while running or the tank will pull a vacuum as fuel leaves the tank and shut down your fuel flow/motor. I just leave my vent open a bit, all the time, especially if it's exposed to any direct sunlight, which will cause heat and expansion. Good Luck!

Re: Fuel stored over winter and leaked

robert graham said:

Your air vent must be open while running or the tank will pull a vacuum as fuel leaves the tank and shut down your fuel flow/motor.

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I assumed that was probably the case, but I appreciate you confirming it. Thanks!