If you think that there may be a possibility that water has contaminated your fuel tank, you should get rid of it.
You ran your motor for an hour, but was this whilst bobbing around on the ocean, or sitting nice and steady at a mooring or alongside?
The motor may not run so well next time you hit some rough stuff and stir up your fuel tank (and water) a bit.

Assuming that we are talking about diesel:
My advice would be to decant as much as you can into jerry cans - depending on how much you have in your tanks of course. Then open up the tank and dry out any water or moisture that remains. Then seal it all up and start again.

Compression lock on a diesel caused by water will destroy it.

Cool, sounds like a plan SA.
Just keep and eye on those water traps for a while and maybe keep some uncontaminated fuel in a couple of jerry cans in case you have to do some draining and flushing of the tanks at sea.

I used to syphon fuel out of the tank thru the filling point to check it was OK.Everytime I check the fuel looked perfect.

12 months ago I was motoring out of the marina and the motor stopped. After draining the glass bowl and replacing the fuel filter I got it going again

after closer inspection of the tank I realised the bottom of the tank was not level with lowest point at the end where the fuel pick point up was.
I took a sample of fuel from that end of the tank, it was disgusting and obviously contaminated with water.
many years of crap had collected to a point it was now being sucked into the motor. I think the pick up was 50mm above the bottom of the tank

I drained and clean the tank, no problems since.

I now drain off two litres of fuel from the low point of the tank once a year to prevent the build up of water contaminated fuel in the tank.
I use the same suction pump I use to drain oil from the motor to drain the 2lts of fuel from the tank.

So the message is make sure you check the fuel from the lowest point of the tank.

It is great to have two water traps in the fuel line. It is even better to have the fuel pick up point higher than the the lowest point of the tank with a bung or ball valve fitted at the lowest point.

Water and sediment naturally accumulates in the bottom of the tank and gets there via the breather as well as via the filler point. This sediment will enter the fuel line when the boat gets tossed around in a sea, especially if the tank is less than 1/2 full and more so when near empty due to the free surface effect (waves in the tank)

A great idea is to visit a tuck or 4WD wrecker and buy an in line sedimenter that has alarm wires so you can wire up a buzzer to let you know the fuel needs immediate attention.

I have fitted a two stage unit from a wrecker that consists of sedimenter with warning wires and plunger pump for bleeding as well as a spin off fuel filter. Then t he fuel passes through a CAV filter/agglomerator.

Don't add anything to your fuel that will dissolve the water allowing it to pass through the engine. Do add fuel treatment to stop bacteria from growing.

A sail always ready to hoist and an anchor rrady to drop when under way as a last resort!

Wayne

southace said..
A good topic has been brought up recently.
i am a little worried I have some water in my fuel tank after my hot water troubles and some plumbing leaking on top of my fuel tank (sender under water as with all the other fittings" the water level did lower before I got a chance to sponge it out of the locker.

So I have bleed both my primary and secondary fuel water bowls and have ran the Perkins for a hour with no missing issues and no water evedent and tomorrow I will try to press my tank...

what are your thoughts? Should I syringe the bottom of my tank to check for water or will it just burn through?

i am a MED2 but from what I remember they don't really touch base on this subject in detail.

regards

Southace, been there done that. My solution was to install an inline sedimenter to each tank prior to the racor filter for each tank. This effectively gives me two sediment and water bowls for eack tank.

Twice a year I run the contents of the tanks through a separate filter fitted to a high volume transfer pump, taken from the lowest point of the tank and returned to the filler port. I guess that I am fortunate that the PO had fitted an access point to each tank directly above the lowest point.

A little time consuming but it WORKS.

Bob.

hey southace I have used the copper tube method with a
outboard fuel primer bulb and it works great, you can target the
lowest corners of the tank even when the tank is still full
works a treat

Hi Southace/Radar,
I like the simplicity of that. What is the OD of the copper tube? Are we talking 5mm or 10mm?

hey shaggy you can buy the primer bulbs in
6mm 8mm and 10mm so you take your pick
they are also good for bleeding your diesel fuel
system when you change your filters at service time
they are a very handy item to have in your tool box