Diesel smell from fuel tank

[Sputnik]

Hi Guys/Girls,
I have a Hunter 356 2002yr, and am trying to find where I am getting diesel smells from. The tank is a Crosslink Poly plastic tank made by Inca.
I have pressure tested the tank and fuel lines using a inflatable dingy pump to about 2psi, but can find no fuel leaks or air leaks using soapy water at all the fuel line connections.
I have replaced the fuel return line from the engine which was giving out a slight odour, all the other fuel lines and tank seem to pass the "damp rag test".
The smell seems to be mainly around the aft end of the tank, and worse after the engine has been run for some time.
I am getting no fuel smells from around the engine or engine compartment.
Has anyone had similar problems with fuel smell "leaching" out of the plastic tank please?
Neil

[clownfishsydney]

You should have a fuel return line to the tank. Is this where it is leaking?

[Pete7]

Originally Posted by clownfishsydney

You should have a fuel return line to the tank. Is this where it is leaking?

He says in his post that he has replaced it, that's not to say the replacement isn't leaking possibly through a poorly made joint.

Pete

[Sputnik]

Trust me! There are no wet or even remotely damp joints at any of the feed/return/filler/breather lines.
The Q I need answered is: has anyone experienced leaks through or leaching of fuel (diesel) smell through the tank walls?
Neil

[SVTatia]

Originally Posted by Sputnik

Trust me! There are no wet or even remotely damp joints at any of the feed/return/filler/breather lines.
The Q I need answered is: has anyone experienced leaks through or leaching of fuel (diesel) smell through the tank walls?
Neil

I can't help with an answer but I am watching with interest - I am considering a plastic fuel tank.
One question though - is the boat new to you and if not, is this something that just started?

[GordMay]

XPE Compatibility:

Diesel Fuel = “B” = Suitable for short term storage less than one year.
➥ https://www.spill911.com/poly.html#D

Diesel Fuel = “S:” = These substances may adversely affect the polyethylene. Products may be suitable for intermittent contact; however, some deterioration in properties may occur. The user should perform qualification tests before or during usage of the container.
➥ https://www.spilltech.com/wcsstore/S...LYETHYLENE.pdf

[meridian28]

Is your vent clear? If blocked pressure could build up in the tank when warm. Unscrew your you filler cap after running and see if there is any pressure.

[sail50]

I get a few drops on top of the racor filters (genset and yanmar) and thats enough to smell deisel inside boat. Check you fuel filters.

[TommmD]

At 2 psi you could still have a slow leak unless you left it overnight & then checked. I replaced the phillips head screws on the fuel sender gage port with socket heads to better tighten them with success (!) on my '95 Hunter.

[Sea Angel1]

Hi Neil,

a nasty problem. I know.
Below deck you will have a large size filling hose to your tank(s) and also a fuel tank vent line. This vent line goes outboard. As diesel fuel has a lot air or foam it will build up some pressure in your diesel reservoir. Make sure that this vent is open to the air and as Meridian xxx is saying it could build up some pressure in the diesel reservoir or filling hoses.
In my case I have had ´the problem" that the filling hose below deck was not properly connected directly underneath the deck fitting and that mainly after refueling there were some drips of diesel fuel were running along these filling hoses towards the reservoir. But you could hardly see these drops. But the smell was terrible. Have a look to all the hoses and lines from the filling tap to your reservoir a.s.o. It my be well woth it . May be there is somewhere a connecting point which is hard to find that causes the problem. Sea Angel Theo
Thread: Diesel smell from fuel tank Reply to Thread

[boeing1]

how long have you owned the boat is the smell recent,,, does not take much diesel to get a odor from what you said about changing all fuel hoses, I would look at the tank installation.

[Frugal]

When storing both petrol and diesel in compliant and non compliant plastic containers I have noticed an osmotic effect through the plastic.
Enough to pick up the odour and on occasions to affect the painted surface they were standing on. A fiberglass tank would be similar and even more so with the fiber acting as a wicking agent. My bet is on the tank.
Cheers

[patprice]

Originally Posted by Frugal

When storing both petrol and diesel in compliant and non compliant plastic containers I have noticed an osmotic effect through the plastic.
Enough to pick up the odour and on occasions to affect the painted surface they were standing on. A fiberglass tank would be similar and even more so with the fiber acting as a wicking agent. My bet is on the tank.
Cheers

Is the tank original?

Presumably it is. Then why do'nt lots of other Hunter 356 2002yr smell?

[thunderhoof]

I have recently replaced some 15 yr old fuel lines because they were cracked and leaking air in. They could just as easily been leaking fuel out if under pressure. Check lines by flexing them and looking for cracks especially near clamps and fittings. I also suggest you lay some sheets of paper towel under the engine, filters and lines to see if any oil spots appear after the engine isbrun for a while.

[Steve Bean]

I don't think properly done fiberglass will "wick" anything though the fibers.