Strong gas odor in cockpit of 305 and soaked sound deadening material atop fuel tank-gctid396348

[Guest]

So I topped off the tank yesterday, and I mean literally. Unfortunately a bit of fuel came shooting out the vent on the side and back up the fuel nozzle. I noticed at hull speed yesterday that there was a strong fuel odor but didn't think much of it. But when I went ashore and came back I got concerned at the smell. Freaked out a bit and found that most of the smell was coming from fuel soaked deadening material. I squeezed as much liquid as I could out, and soaked it up with rags. I jiggled the vent line which is slightly loose, but not scarily so. My guess is it was a little loose and the volume of pressure coming from the fill side was just too much. Turned the batteries off, opened the canvas and all hatches and proceeded to not sleep all night.

Any ideas odor is all but gone this morning! A bit freaked out I might have been extremely lucky yesterday.

[Guest]

It sounds like something is leaking at the top of the tank. That would be the sending unit, full hose, or vent hose. I haven't tried to access those on my boat, so I don't know if you can get to them easily, but that's what I'd look at first.

[Guest]

aa2300 wrote:
...Turned the batteries off, opened the canvas and all hatches and proceeded to not sleep all night.

A good course of action. However, fumes are heavier than air and could be sitting down in your bilge even if the hatch was open. Anything wired to your battery directly - such as a bilge pump, trim pump, etc represents a potential to spark. By the book, you should evacuate the boat and call the fire department if you coudln't get a strong odor of gas to go away. For those of us more self-sufficient, first put all passengers up on the front bow with PFD's on, portable radio, etc. Then try to hand-fan the fumes out of the bilge to diffuse the fumes then turn the blower on. The blower should stay on until the source of the fumes could be removed, or else return to port, radio for help, etc.

aa2300 wrote:
I noticed at hull speed yesterday that there was a strong fuel odor but didn't think much of it.

Any time you smell raw petroleum fumes on a boat you should snap to attention.

aa2300 wrote:
found that most of the smell was coming from fuel soaked deadening material. I squeezed as much liquid as I could out, and soaked it up with rags. I jiggled the vent line which is slightly loose, but not scarily so.

Seems reasonable that the overflow caused a temporary lingering of fuel / fumes. In my opinion, topping off a fuel tank on a boat is dangerous, since it could leave standing fuel in the fill and overflow lines, where it could leak. It will also test the seal on the top of the tank, which may leak.

I would check and fix all the lines mentioned. When filling the tank, you can deduce how many gallons to fill it to within 5 or 10 gallons and put in no more than that. Fair Winds!

P.S. This is also a good time to inspect the blower hoses to make sure a) they haven't come loose from the blower housing or the through-hull vent housing, and b) there are no tears or rips in them, especially higher up which would compromise the sucking of fumes out of the bilge

[Chief_Alen]

You have a bend in the vent line? Fuel may still be in there in effect cutting the vent off and causing a vacuum in the tank. Fuel should evaporate quickly but the rags will still smell of fuel for a long time. Any hole in the gas tank IE:sender, pickup vent etc can leak look at them all see where it is leaking from. You could pressure test the tank.