How to pressure test a stanless fuel tank?

Miller · 10 October 2009, 15:14

Is there any simple way of pressure testing a fuel tank that is fitted in situ on a rib?

The tank was supposedly pressure tested last year but I want to double check as might have some water in it.

Failing that anyone know where it can be done around the Plymouth area that would come to the boat?

Thanks

chewy · 10 October 2009, 18:45

You'll have to drain all the fuel and vent the tank.
Black all holes off and pressurise to say 5-10psi, lock the pressure in and monitor for a few hours.
What pressure was it tested to last time?

Are you losing fuel out of the tank?

Miller · 10 October 2009, 19:17

Quote:

Originally Posted by chewy

You'll have to drain all the fuel and vent the tank.
Black all holes off and pressurise to say 5-10psi, lock the pressure in and monitor for a few hours.
What pressure was it tested to last time?

Are you losing fuel out of the tank?

No, its seems I have got some water in there. I m pretty sure its not leaking else I would have fuel leaking into the transom well and there is nothing

chewy · 10 October 2009, 19:17

So you think it could be through the filler?

Poly · 10 October 2009, 19:27

Quote:

Originally Posted by chewy

So you think it could be through the filler?

or just condensation?

jwalker · 10 October 2009, 22:06

Not in anyway an officially recognised method but rather than pressure testing, vacuum test it. Seal the tank, attach a tube, suck hard and block off the tube with your tongue. If it's sealed, you'll feel the partial vacuum sucking. I sounds crude but it's effective anytime you need to check for sealing.

captnjack · 10 October 2009, 23:57

don't suck on gas vapors

petrol is thinner than water and if its not leaking out, the water got in from bad fuel, through the fill, or from condensation.

Dirk Diggler · 11 October 2009, 07:43

Quote:

Originally Posted by chewy

Black all holes off and pressurise to say 5-10psi,

If it's baffled 10psi may blow all the welds! 3-4 psi is fine.

mdt · 11 October 2009, 07:46

Get an old bike inner-tube cut it and jubilee clip one end closed and jubilee the other end over the filler flange on the tank.

Seal up the vent and fuel out pipe.

Get a bike pump and pressurise the tank and check for the leek?

Empty the fuel first

JSP · 11 October 2009, 08:42

Quote:

Originally Posted by captnjack

don't suck on gas vapors

Yeah but he'll giggle his socks off so the job wont seem as bad.

chewy · 11 October 2009, 09:27

Quote:

Originally Posted by Dirk Diggler

If it's baffled 10psi may blow all the welds! 3-4 psi is fine.

Lol, I was just thinking of the tanks we have, built like a brick out house!

Hightower · 11 October 2009, 09:29

I wouldn't bother with leak testing right now. I would drain off the bad fuel and clean the tank if you can. Brim the tank off and have a good sniff around. If it's leaking then you'd smell the petrol vapours.

I would guess that water got in the tank by contaminated fuel, though the filler cap seal or my guess would be the tank breather. I am always real carefull when washing the boat down around my breather and fuel fill fittings.

Miller · 11 October 2009, 12:47

Thank you for everyones help, i ll give it all a try, its now in storage until next year so plenty of time to look for the problem

Hightower · 11 October 2009, 14:37

Quote:

Originally Posted by Miller

Thank you for everyones help, i ll give it all a try, its now in storage until next year so plenty of time to look for the problem

Well if it's going in to storage I wouldn't buy petrol now as it'll go off before the start of next season.

Miller · 11 October 2009, 18:18

Gonna pump all the fuel out over the winter and have a look try and find if there is water there somehow?