Diesel in the Bilge ('05 H41DS)

[SV Bella]

I was topping off my main tank yesterday. I had a crew member put the diesel in the boat. I think he over filled the tank. Some diesel was sputtering out the air vent and ran down the side of the boat when he was filling the tank. Today I look in my bilge and there's almost a gallon of diesel there. I cannot find where it came from. WHERE WOULD THIS HAVE LEAKED FROM?

I've taken every floor panel off. Removed the aft mattress and removed all panels there. I emptied the stern lockers and got in to visually look at the backside of the fuel cap and vent cap. I see no signs of diesel anywhere around the tank. I can't see past the rear of the bilge where the Structural Grid (the pan) meets the hull. That is where it's coming from. I've vacuumed out the diesel. A small amount is still coming from the back end of the bilge. Appreciate the answers.

Heading to the Keys in a week - my first real trip.

 

[kloudie1]

I had a cracked injector return hose that leaked like that. A friend had a cracked vent hose that leaked like that.. I'd check the vent hose for cracks and tight connectors.

 

[SV Bella]

I found the leak. It's on the top of the axillary tank (we did not add fuel to the axillary tank yesterday). What I would call the sending unit has a slight leak. There is a hose between the main 35-gallon plastic tank to the axillary aluminum 18-gallon tank to level excess. The second hose to pump from the axillary tank to the main tank has a petcock, and it's closed. I believe the 18-gallon tank to be original from Hunter. That's just a guess. Solution: 1. Seal the sending unit. 2. Don't overfill in the future. The previous owner had some absorbent towels there. I think this was a known problem.

I ran the engine an hour today. I then pumped a little fuel over from the axillary tank.

 

[kappykaplan]

Nothing like some good detective work! Glad you got this sorted (identified) before your cruise.

 

[Ralph Johnstone]

1. Seal the sending unit.

Hard to tell what the flange of the sending unit is sealed with.

From the tidy appearance, it may just be a dry gasket. I suffered the same problem from a first overfill with a weeping fuel leak on a factory original gasket installation.

The only thing I've ever seen stick to poytethylene is Permatex #2. It's so bad, it'll leave permanent stains on the boat two berths down from you . It's rated for all petroleum fuels.

This was taken after I resealed ALL the fittings on top of the the fuel tank. Slightly overfilled the tank and everything was sealed with not a drop around any fitting.

 

[senang]

You can use a gasket cut from a thin sheet of cork. Cork will seal and not deteriorate.

 

[SV Bella]

We bought a new rubber seal from West Marine. The old seal that came off still looked good. What fixed it was putting some sealant also purchased from West Marine. The stuff came in a small can and had a brush affixed to the lid much like rubber glue. It was called Aviation Form A Gasket. We coated both sides of the gasket and the surface of the aluminum tank. Plus, the new seal came with washers with rubber on the backside. Those washers spread the effectiveness of the screws and helped seal around the screw (plus we put the stuff on them too).

Probably the real lesson is once you hear or see gurgling in the air vent hose to the tank, stop filling. I made the mistake of letting someone else do it. I was down below flushing heads while a 3rd person sucked the black tank.

Heading to the Keys tomorrow. 7-10 days.