Gas smell in Aft Cabin

Tim60

Tim60

New Member
Oct 6, 2021
10
Boat Info
1996 Sundancer 330
Engines
Twin 350's VDrives
I purchased a 96 Sundancer this past year. The boat sat in dry storage for 9 years. I am told the dealer went through the boat and did $7K worth of maintenance. When I arrive at the boat after being gone for 2 or 3 weeks and go below I notice a strong smell of gasoline. The boat is always closed up when I am not there. I check the engine compartment and see no signs of a leak. I have cleaned the gas tank vents with no cure so far.

Has anyone else experienced this?
Ideas?
Suggestions?
 
Ventilate, ventilate and by the way ventilate.
Do not turn on any electrical switches except the battery switch and the bilge blowers.
There should NOT be a "STRONG" smell of gasoline in the cabin ever.
The cabin and the engine spaces are separated, most electrical devices in the cabin are NOT "ignition protected".

Now we all have different ideas of "strong" when it comes to things like gasoline but even a "hint" of gasoline anywhere but in the engine room is a serious concern.

How do you store the boat? It's still in dry storage? Covered?
You wont "see" a small gas leak it evaporates quickly, run your hand under the spin on filters, fuel pump, lines nothing should be wet.
 
hughespat57 said:
Ventilate, ventilate and by the way ventilate.
Do not turn on any electrical switches except the battery switch and the bilge blowers.
There should NOT be a "STRONG" smell of gasoline in the cabin ever.
The cabin and the engine spaces are separated, most electrical devices in the cabin are NOT "ignition protected".

Now we all have different ideas of "strong" when it comes to things like gasoline but even a "hint" of gasoline anywhere but in the engine room is a serious concern.

How do you store the boat? It's still in dry storage? Covered?
You wont "see" a small gas leak it evaporates quickly, run your hand under the spin on filters, fuel pump, lines nothing should be wet.
Click to expand...
 
Stored on the water in a covered slip. No noticeable leaks anywhere.
 
It’s possible one of the fuel tank has a pinhole leak. If you can’t find an obvious source, you might need to get the tanks inspected.

Any water sitting in the bottom of the tanks for an extended period could cause this.

I would consider the boat unusable until the source of gas vapor is found and fixed.
 
I have the same boat and there is absolutely zero gasoline smell on my boat and that includes in the bilge itself (and my boat has carburetors).

Start by taking out all of the cushions in the aft cabin and sniffing in the storage that is under the seats. Smell inside the floor hatches too. There should be no gasoline smell at all.

The tanks in a 330 are not in a wet location so corrosion leaks should not happen. If there is a tank leak, I suspect it is in a fill tube, vent tube, or fuel gauge sender gasket on one of the tanks. None of which are easy to access. But you need to find the source for sure.

What about the gas lines? Are they all solid with no leaks or smell? Rub a cloth over them and smell the cloth. There should be no gas smell.
 
Sounds like the seller gave you a problem.
 
With todays technology, isnt there some kind of thing you can buy that detects the smell of gas as you go around the boat and point it? Like those radiation detectors on tv?
 
Had a sender gasket that was way over tightened on my 340.
I replaced the sender and gasket and all was good.
 
I’d be inclined to look first at fuel filters or any fuel system component that was recently serviced. Assuming they were changed out as a part of the get ready maintenance work, leaks can happen if the tech was interrupted while doing the work and a gasket did not seal or a thread was not fully tightened. I had a small fuel filter leak that created quite an odor, and traced it to a filter that leaked. Found it by spotting a stain beneath the filter caused by the dye in the fuel.
7BFE3D0A-6593-4F05-B4C4-B0340E524E73.jpeg
 
My question is the fuel lines themselves. 25 years is a long time on fuel hoses if they haven't been replaced. They literally can weep fuel at bends and fittings.....especially ethanol fuel.

Your engine room is a tight fit so it will not be an easy task to find the problem. If the smell is in the aft cabin it is in the engine room.
 
unless your tank is under the aft cabin. Check the fuel sender unit also
 
No matter what kind of fuel that is in the tanks, they tend to "breath" as temps and barometric pressures rise and fall, with the associated moisture being drawn into the tank with every cycle. It sure can lead to a pin hole through the underside of the tank where it's not obvious.
We purchased a '92 last year, and don't have any fuel odor, even down in the engine "dungeon". That's one advantage to living in our part of the country, is that the air tends to carry very little moisture with it. 'Sucks having dry skin issues, however...
My money is with @PlayDate in that the lines definitely get brittle with age, especially with the ethanol fuel. I've had them where fuel will actually "sweat" through the outer jacket, as the inner lining begins to fail without any obvious external indication.
 
All very good suggestions. I bought the boat last Fall and asked the seller to hold on to it and deliver in the Spring. They did and I immediately started with an issue. As soon as we launched it, I had a Shaft seal go, leaking water. They pulled it back out and I had them replace both. After all if one goes can the other be far behind? I keep the boat in the water at Dale Hollow Lake in Tennessee. Very humid there as people mentioned humidity in the comments. I will be back to the boat and check the fuel sending unit first then the lines. If after that I don't see anything it will be time to break out the wallet and have a mechanic go through it. She is a 25 year old boat and sat on the hard for 9 years. Things that are supposed to stay wet did not and dry rotted I am sure. I knew that when I bought it. The motors only have slightly over 300 hours and other than the couple of mechanical issues, so far so good and I am sure she will be a great boat for me.
 
Pirate Lady said:
snt there some kind of thing you can buy that detects the smell of gas
Click to expand...
There is. I have never thought to use it until your comment. The general name for them is PhotoIonizing Detector (or PID). We use them routinely in the environmental consulting business. You could also use a Combustible gas indicator (CGI). While the PID (See RAE industries) gives a quantifiable number and is expensive for such a use, the CGI (1/6 the price of the PID see Grainger Supply for various manufacturers and price) will give a qualitative result. Never thought to use either for fuel leak detection in a boat but they would be good to pinpoint the actual spot down to a square centimeter (if used properly).
 
I owned a 95 330DA for many years and knew the boat very well. You say aft cabin, but have you poked your nose around in the engine compartment? Start at the source, the tanks, and follow the lines all the way to the carbs, assuming you have carbs, looking for damp, wet spots, cracks in lines, etc. Shop vac dry the bilge, let it sit, check for dampness.
 
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