Water in fuel tanks again

[JumboTed]

Hi all,

Recently took both fuel tanks out of our boat to get them cleaned. They were cut open cleaned and welded back together. They were then filled full.

Yesterday I took the boat out for the first time since December after major work had been completed. The engines both ran like a dream, after all my previous work but I found quite a lot of water (250ml) in one of the racor 500 filters. The engines run on a tank to engine set up so there are two fuel tanks and are independent of eachother.

My question is where could this be coming from in others experience? Any help greatly appreciated!

 

[Mr Googler]

Did you replace seals on the deck fittings?

A common place for water entry

 

[JumboTed]

Not yet! I will try that tomorrow!

 

[Simi]

More than likely it’s getting in you filler caps check the seals

 

[Farmer Piles]

Sounds like it's more than could be put down to condensation. Frustrating.

 

[PCUK]

Also fit a Dipper from Marine 16 to endure it never happens again.

 

[Simi]

Water may be sitting around your filler caps and running in

 

[Seastoke]

It could be the fuel

 

[Orthop]

two tanks independent...
o-ring ?
Often the water in the fuel tank is rainwater. Check the air ventilation pipe if there is an swan neck ( hope I found the right term ), so that the rain water can not get into the tank over the air vent outlet...I would also change the fuel filter / pre filter on the engines...Be careful as some engine don't like small amounts of water in the fuel...
When a inspection hatch in the tank is installed, it might be helpful to remove all the water and clean the tank and treat the fuel, i.g. Grotamar.

 

[Treebore]

I had a similar problem a few years ago, after a lot of searching I eventually found that rainwater was leaking around the fuel filler fitting (between it and the deck), a loose jubilee clip on the fuel filler hose meant that water ran down into the fuel tank. I was surprising the large amount of water that could collect in the tank this way. Good luck.

 

[Portofino]

Next time they are out with a guy armed with welding kit ask him to weld in a tank drain cock at the bottom somewhere .
Next ask him to weld in some sight glasses starting ( via a cock ] at the bottom = you might be able to see the water then before it’s sucked to the racor and then exercise the new drain cock .

 

[Bandit]

O rings on filler caps cost pence from a seal supplier, they degrade with time and perish from the outside in, leaving cracks in the ring, buy ten years worth and change them annually.

Check whether the tank breather can let water in.

My tanks have a sump of about one litre, a cylinder about 4 inches wide and about 6 inches deep looking at the drawing ( I cant see sumps , built in) and a stripping line, a stainless pipe from tank top to bottom of sump, it has a blank on tank top. The natural movement of the boat means the water and crud tend to drop in to the sump and stay there until end of season when we strip them out with a Pella pump or if I have a problem if I see water in my Racor primary filters. When I replaced the tanks in my Fairline Sedan 36 about 20 years ago , the tanks were built with a sump of about the same size at a low point in the tank with a drain cock below.

In an ideal world all fuel tanks would be built with a a sump and either a drain cock or a stripping line.

If you have water in your fuel you will be developing a fuel bug problem, it is essential that a good proprietary biocide is used, I use Grotamar 82 which unfortunately is limited to professional users, I understand Marine 16 works in a similar way?

 

[JumboTed]

Thanks for all the help. This was the state of the filler cap seal on the effected tank. Feel stupid I didn't realise this could have been the problem in the beginning! Fingers crossed that's it all sorted now.

 

[Fishtigua]

We've fitted loads of these over the years. I think all new tanks should come with these for cleaning and a sump and drain for safety.

Inspection Hatches | Tek-Tanks

 

[Bandit]

Don't know who Fishtigua is but, exactly the same we use Tek Tnk lids but why oh why build a tank without a sump and drain or stripping line. So much of our work is dirty fuel, water and fuel bug and corroded tanks so fuel tank replacement..

Its good for business but not the bloke who owns the boat and is stuck with the bill.

Build a boat for the long term not the boat builders accountant and charge a fair price, its a false economy.

 

[Rum_Pirate]

So can you tick off each these possibilities?

• Deck fitting leaking ? Corrosion etc.
• Filler cap O ring ?
• Condensation ?
• Fuel source ? Change supplier.
• Somebody that dislikes you and your filler cap is not locked? ?
• Sink/shower drain pipe incorrectly connected to the fuel tanks and not the holding tank? ??