How to make a twin set up pointless!

[GordyP]

I have two tanks on the rib set up so you can draw from both, just one or one tank supplying each engine. I have been fairly complacent about seperating the fule between the engines and have been running wiht fuel coming from both tanks. In practice this means that fuel is pulled from the deck tank first before it starts to pull from the under deck tank.

Went out for a dive on Sun, I was aware that I should really use some of the fuel in the under deck tank so it didn't become stale so switched to that tank alone. Trundle through the marina, open up once outside to cruising speed, get about 300 yards before the 'water in fuel' alarm went off and both engines similtaneously stop. Bugger. We eventually got a tow back into the marina where I flushed fresh fuel through the engines to get rid of any water.

Went down to the boat on Monday, pumped a good ten litres of fuel from the bottom of each tank. The lower tank had about a thrid of a litre of water in it. Replaced the plugs on each engine and got them going again.

I think the water in the lower tank must just be a build up over a period, there was enough of it that the pick up in the tank has pulled pure water through, the engines didn't enjoy this!

I will in future have seperate tanks supplying each engine, its a bit pointless having twins when both end up stopped due to crappy fuel. I think I may for a while also pump a sample of fuel from the bottom of the tanks to check for water.

So if you have a twin set up, don't be a lazy sod like me, make sure you keep the fuel supply seperate for each engine.

[Simon B]

What did the in-line fuel water spearators look like, they'd be full too surely?
Some people carry spares, we dont, there is a whole debate around whether we should break into our fuel line to add an aux tank connection point but on a 160 litre main tank is this really required?

[GordyP]

I have a water seperator at each tank as well as the ones on the engines themselves, they were full of water. I change them every few months to try to keep the fuel flow to the engine pretty clean, in this instance there was just a glut of water in the bottom of the tank.

[GordyP]

Water was not a build up, spent yesterday removing the top tank, console and oil tanks, got the in hull tank out and several of the welds are very gently weeping. At least I now know where the problem lies.

[martini]

I would have thought that if the cracks are bad enough to let that much water in, they'd let fuel out at a much higher rate which you would notice? smell/consumption etc

Obviously the cracks will have to be repaired but I think you will still need to use both tanks to prevent water/condensation building up.

My 28 has 2 tanks under the deck, I always use one tank for each motor except rare occasions when I might use one to change the ballast to suit conditions.

Get water separators with a drain tap on them then it's easy to drain bits of water regularly before it can get up to the motors.

It's unfortunate that the tank has split, they are really well made in the Halmatics

[GordyP]

Unfortunatley its wasn't an original Halmatic tank, I'm going to get a replacement tank fabricated to fit the channel in the deck. I intend to use both tanks supplying an engine each to prevent the need for a tow in the future. Good idea to change the seperators over to ones with a drain tap on them and a glass bowl, I'll maybe change them at the weekend.

[martini]

I used these ones with built in primer but they are bloody expensive:
Racor Filters, Racor 400 Spin-On (Petrol)

Standard ones are much cheaper:
Racor Filters, Racor 100 Spin-On (Petrol)

[Simon B]

Yes, but the element is not that expensive at £16.47 so £32 per year, unless it's hideously corroded you will not need to replace the body or the clear bowl at the bottom.

Do you have any small inline filters inside the cowl of the engine? Some people swear by a last line of defence for their filtration. The worst instance I have experienced myself was from a dodgy fuel coupling inside a section of above deck trunking. It was allowing seawater in when under negative pressure (when engine was running) This filled the water separator up.

[GordyP]

Thanks for that, they look like they'll do the job. Worth paying a bit more rather than ending up with knackered injectors from mucky fuel.

[9D280]

Just a thought - if you are planning in the fullness of time to buld / buy a new under deck tank, would it be worth making it a "twin tank" and totally separate port & starboard fuel systems?

[GordyP]

Originally Posted by 9D280

Just a thought - if you are planning in the fullness of time to buld / buy a new under deck tank, would it be worth making it a "twin tank" and totally separate port & starboard fuel systems?

At the moment there is a sealed channel in the deck which houses the under deck tank which is about 130 ltr, there is also an extended range tank which is bolted to the deck and doubles up as a three person seat. The ideal solution would be to alter the deck itself and have two 130 ltr under floor tanks, but I'm not sure i have the time to get into that kind of work. I am considering altering the layout over the winter to a double console which would have a fuel tank inside it to replace the top extended range tank.

In any event I won't be as lazy to have both engines running off the same tank again, nothing worse than knowing that you could have avoided a breakdown by not being such a lazy git!

Thanks for the good suggestion though.

[9D280]

I maybe didn't explain that too clearly.... when you replace the 130L tank, when the replacement is built, have a divider so it is essentially a pair of 65L "siamese tanks" in the same package space. Granted the extra filler might be a minor pain to route somewhere suitable.

[GordyP]

Originally Posted by 9D280

I maybe didn't explain that too clearly.... when you replace the 130L tank, when the replacement is built, have a divider so it is essentially a pair of 65L "siamese tanks" in the same package space. Granted the extra filler might be a minor pain to route somewhere suitable.

No I understood, I will be keeping the above deck tank which is also 130L so will retain the two seperate tanks (130 Ltr each). Need the 260 Ltr capacity for some of the longer distance stuff.

If I was only keeping the under floor tank I would have taken your advice on the split which makes good sense.

[GordyP]

Sooo, the boat has been at the workshop to try to get the engines sorted as a result of drawing through salt water from the bust tank.

Oh, how I've laughed at now having to replace 12, yes thats 12 injectors.

Bloody boats.

[Pikey Dave]

Gordy, just out of curiosity, have you opened any of the injectors up to see what the inside is like?

[GordyP]

They are all rusty apparently, I'll get to inspect them when I go to pick it up.

12 new injectors ordered today, hopefully have the boat back in a weeks time.

I can get photos if anyone's interested in seeing rusty injectors!

[Pikey Dave]

If they are scrap, I'd be interested in having one to dissect just to satisfy my curiosity(ok I'm wierd) I'd happily pay the p&p

[GordyP]

Originally Posted by Pikey Dave

If they are scrap, I'd be interested in having one to dissect just to satisfy my curiosity(ok I'm wierd) I'd happily pay the p&p

In which case I can supply a selection! I'll let you know when i have them.

[Chris]

Originally Posted by GordyP

Sooo, the boat has been at the workshop to try to get the engines sorted as a result of drawing through salt water from the bust tank.

Oh, how I've laughed at now having to replace 12, yes thats 12 injectors.

Bloody boats.

Noooooo

Sorry to hear of your nightmares...

What did you pay for the injectors in the end (i'm almost afraid to ask !)

[Chris]

Originally Posted by Chris

Noooooo

Sorry to hear of your nightmares...

What did you pay for the injectors in the end (i'm almost afraid to ask !)

Oh and if you can send me a couple I would like to see inside them too