Gas Fumes On Boat

H

hawkeyes01

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Joined
Jan 29, 2010
RO Number
31963
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51
Hi everyone,

We have a 1989 Carver Santego. We just filled it up with fuel for the first time, we normally just put in 40 or 50 gallons at a time in the past. After it sat for the night we returned and the cabin had a very strong gas smell inside. I went down into the engine room and it smelled normal, the strongest smell was in the cabin. Running the blowers seemed to get rid of it, but it came back after a while. I've checked both tanks and all fuel lines and everything is bone dry.

Is it possible that there is a ventilation issue? Has anyone else experienced this on their boat?

I'm just looking for ideas on what to check next.

Thanks everyone.
 
If you can smell gasoline in the cabin something is not right. Be careful. Inspect every inch of the fuel system, from the through deck fill port, fuel intake line, fuel tank, fuel level sensor, fuel supply line, valves, fuel vent line, fuel vent through hull/deck fitting, fuel filter housing. Make sure you inspect everything, if some part is hidden, get access (it is generally the areas that are hidden that have the leak) don't fool around. Be safe, good luck.
 
this is a VERY serious issue as gas vapors are highly explosive. the fact that the smell is in the cabin is even worst since most stuff there is not ignition protected as it is in the ER.

first, open every hatch, door etc... shut down shore power AT THE DOCK breaker to make sure you don't get a spark at a breaker in the cabin. shut down the battery switch (they are ignition protected).

where is the fuel tank(s), filler and vent line. often on expresses the tank is under the berth in the mid cabin. check for evidence of leak there. then check the filler hose and vent connections. i'd suspect a bad hose or clamp, probably on the vent line, otherwise a tank issue. do you see any evidence of gas in the bilge? if not, then it may not be the tank itself but just the vent line.

take this very seriously, in doubt get help from a mechanic or marina.
 
Thanks everyone - 12V and 120V power is off and all windows are open. I'm wondering if it is actually exhaust and not fuel vapor. If exhaust was leaking into the cabin, that would set off the CO2 monitors though wouldn't it?

I'm going down to look around again today. I went over all of the fuel tanks yesterday, rubbed everything down with rags to see if I could pick up any residual fuel, checked the bilge (it was dry) - I wasn't able to find anything anywhere.

I guess it's time to call the mechanic if I can't find anything else today.
 
a hint is that it is full for the first time. look at the vent and fill lines
 
I'm focusing on the vents - I have full access to all the fill lines and they seem fine. Anyone ever heard of gas line vents becoming clogged?
 
Yes bugs/insects will nest in the fitting or the vent line. Spiders will spin webs on the flame screens. If you filled the tank full and the fill process went smoothly, IE no blow back through the deck fill, the vent line should be open, now it may be open into the bilge area or somewhere other than where it should be venting. Twenty plus year old fuel tanks, look for pin holes in top or upper sides. Maybe time for an air test of the fuel tank.
 
Either the vent or even the plate that covers the fuel gauge sender has a gasket that dries out and rots and can leak when the tank is full. If you can get at it, not a difficult repair, just get a new gasket and be careful with the bolts...
 
clogged vent will cause issues when filling the tank (gas spitting back out). but a bad vent hose or a vent that's disconnected will cause these issues.

you wouldn't be smelling exhaust if the engine isn't running and the smell is very different.

i do hope that you have a vapor detector in the bilge... it should go off. it's a MUST HAVE on a gas boat.
 
Had the same problem a couple of years ago.
Only noticeable when tanks were filled up.
Fix was what LouC suggested.
If you can look on top of the tanks very closely.
That's how I found my leak.
 
I had the same problem in mid July, Funny thing was I was on a 10 day cruise, and had filled up twice in the four days befor it happened!

Filled up at a marina accross from where we were staying, everything was fine. Got to our slip, 10 minutes later, and the whole cabin smeel like gas, found a leaky gasket on the gauge sender. Ventilated everything, ran the motors for about an hour to lower the fuel level, and dealt with the leak when I got home.

I was very concerned that I would brak a screw while doing this and did not want that to happen 100 miles from my dock. When I got home, it took 10 minutes, and every screw came out like it was jsut put in the day before. Not bad for a 24 year old boat.
 
Another scenario,

This happened to me a couple years ago. I would have a little bit of a smell in the cabin after fueling but not in the bilge. My gas fills are at mid ship on the side decks and about 2 feet forward of the side deck drains which run down through an open but closed in area below the side decks. Turned out I had a crack in the down pipe of the drain and if the fuel burped a little it would run down the side deck and down the drain and the fumes got into the area below the side decks. I replace the drain and the problem went away.

Good luck

Niles
 
Thank you so much everyone for all of the responses. I went back to the boat yesterday and reventilated everything until there was no hint of fumes and then ran the engines for a while to lower the fuel level a bit. If I go back today and the smell has decreased, then I'm going to focus in on the gaskets. After three searches, I have not been able to find any fuel anywhere, and the bilge is bone dry.

Thanks again for all the responses, it's helpful to hear how people have dealt with this issue in the past.
 
On my old 2895 one of the tanks actually developed a leak. Depending on where the leak is you may be able to put fuel in the tank without realizing there is a problem. You said this was the first time you filled it up. Is it possible that above a certain level there's a hole in the tank?? Better check that out also!
 
I bought a 1998 Mariner and had the same problem. Found there were tiny pin holes in the gas hose. While being filled it leaked and created the fumes. After removal and the hose was straightened you could see them, but they were not visible while compressed in the boat. After they were replaced, the smell was gone.
 
I had gas fumes in the cabin during a recent trip. It turned out to be a small leak in a loosened bolt on the fuel/water separator filter. Tightened the bolt, cleaned up the bilge, ran the blowers; no more fumes. Another thing to check.
 
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