How to find leak in fuel tank (if there is a leak)?

[Adetheheat]

This is similar to another post. The cockpit of my Beneteau Antares 750 smells of fuel. But the fuel tank is outside and the engine is also outside outboard.
So logically the only way the cabin could have this smell is if there is or was a leak or spillage from the fuel tank into the bilge.
Agreed?
So to find the leak I would have to feel around the fuel tank and pipes looking for moisture? Does this sound about right?
Thanks

 

[Freebee]

its been very hot in the uk, petrol in tanks will vaporise and leave the tank via a breather, where is the tank breather?? also i would have a look / feel around the tank and fuel lines - as you suggest.

 

[Freebee]

on your other thread about vacuums........ i would hold back using anything sparky whilst you can smell fuel fumes. clear the fume problem first

 

[rogerthebodger]

Pressure test is the best way to find a leak in any tank or other enclosed space.

Block all inlets and out lets and apply a small pressure using a hand pump and lisson for the hiss

if no hiss the check the pressure after am hour

 

[Brc45]

Pressure test is the best way to find a leak in any tank or other enclosed space.

Block all inlets and out lets and apply a small pressure using a hand pump and lisson for the hiss

if no hiss the check the pressure after am hour

In aviation, they check it by spraying soapy water on pressurised wing tanks, or submerging them, if small enough.

 

[BabaYaga]

Pressure test is the best way to find a leak in any tank or other enclosed space.

Block all inlets and out lets and apply a small pressure using a hand pump and lisson for the hiss

if no hiss the check the pressure after am hour

One simple way of applying a slight pressure is to cut a bicycle tube, block one end and put the other to a tank fitting and then inflate. As mentioned, soapy water will reveal where the leak is located.

 

[footsoldier]

The oft-used method to find slight leaks of liquids is to deposit paper towels (preferably coloured) or talcum powder in the strategic places and then check regularly for staining.

 

[rogerthebodger]

When steel canal boats were being build we would paint the outside of the welded joints with white wash and paint the inside with diesel fuel. Any pin holes would show up with a diesel stain on the white wash on the outside.

Big boats hulls are not easy to pressure test with soapy water

 

[SvenH]

On my previous boat I found my jerrycan )petrol) to be empty at some point.
Never touched it whilst in storage, put it there full.

Guess where the interior smell came from?
Found out it had a very poor seal as it was very, very cheap...