Fuel Leaking from filler cap. I have no idea on this one.

[Trooper583]

A few weeks ago I winterized my boat. As part of my normal procedure, I topped the fuel off and added plenty of stabilizer.

Before I go any further, I need to say, I have a 1995 Rinker 212 OB with a 40 gallon aluminum fuel tank mounted under the deck, just forward of the engine. The gas cap is located on the rear starboard corner. I keep my boat over the winter at a family member's house. a few days ago they called and said they could smell the strong odor of gas coming from around the boat. After I inspected it, I found that fuel had leaked from around the gas cap and down the stern of the boat. It of course stained the gel coat and I dismissed it as a fluke. At first I thought that perhaps the gas had spilled out when I was trailering from my house to the storage location. However, the family member called again today and said they could smell gas coming from the boat again.

Anyone got any ideas? It almost sounds like the tank is somehow building pressure and pushing fuel out the fill cap. I should also say that the batteries have been removed for the winter.

As always, many thanks to my fellow Iboaters, I'm sure you guys will help me figure it out.

 

[Stachi]

Re: Fuel Leaking from filler cap. I have no idea on this one.

If you topped off the tank in cold weather , and have had a few warm days since top-off...the fuel is expanding . Drain some out.

 

[Trooper583]

Re: Fuel Leaking from filler cap. I have no idea on this one.

thanks for the reply, I actually considered that but didn't think that temperature changes would force that fuel change that much. I didn't have any ideas on what to do but I think I'll go siphon a a half gallon or so out and see what happens. Thanks

 

[Stachi]

Re: Fuel Leaking from filler cap. I have no idea on this one.

You are welcome. I hope this turns out to be the fix for you. If you had topped it off up to the fuel cap on a cold day...it probably will be the fix.

thanks for the reply, I actually considered that but didn't think that temperature changes would force that fuel change that much. I didn't have any ideas on what to do but I think I'll go siphon a a half gallon or so out and see what happens. Thanks

 

[Stachi]

Re: Fuel Leaking from filler cap. I have no idea on this one.

For what it is worth , have you ever sucked a plastic portable fuel tank dry with an outboard engine ? It collapses the walls of the tank. The fix for that , is to close the vent and cap , and set it out in the sun for an hour...the fumes alone in the empty tank will expand and return the tank to it's former shape.

 

[smokeonthewater]

Re: Fuel Leaking from filler cap. I have no idea on this one.

while you are there, siphon out about 3 gallon instead of 1/2

 

[Stachi]

Re: Fuel Leaking from filler cap. I have no idea on this one.

^ 100% good point....

 

[sqbtr]

Re: Fuel Leaking from filler cap. I have no idea on this one.

Kinda makes me wonder why it's not coming out the vent.

If the cap is leaking fuel out it can also leak water in, maybe check your cap o-ring and make sure your vent is clear.

 

[oops!]

Re: Fuel Leaking from filler cap. I have no idea on this one.

yeah, this is a vent issue.....and i think you have the kind of cap with a small vent hole in the cap.....i would loose that system.....if gas can get out the cap....water can get in

 

[Stachi]

Re: Fuel Leaking from filler cap. I have no idea on this one.

Good point...I would check and see if it didn't come out of a thru-hull vent as well as the cap. My cap o-ring needs replacing , but I keep it covered all of the time. It is on the list for the spring...lol

 

[Home Cookin']

Re: Fuel Leaking from filler cap. I have no idea on this one.

through hull vents can also let water in. I prefer the vented cap for that reason.

Also a cap that leaks fuel being pushed up won't always let in water, flowing down; depends on design and other circumstances. Recall the loose metal caps on the old metal cans; gas could slosh out but rain water and spray would not get in.

 

[ppod]

Re: Fuel Leaking from filler cap. I have no idea on this one.

Had a similar problem. It doesn't take much of a temp diff to cause gas fumes/vapors to expand and contract. The high point of the tank during storage formed an air pocket that couldn't vent. During cool times, the tank sucked a bit of air which went to the high point. During warmer times the fuel expanded forcing fuel from my vent. This will happen untill enough air is in the tank to get to the vent. My problem was solved by lowering the bow of the boat during storage allowing the air pocket in the tank to be at the end with the fill and vent attachment. No more problem.
Good luck, Dave

 

[NHGuy]

Re: Fuel Leaking from filler cap. I have no idea on this one.

Dave, you smart fella!