water in petrol tank?

[Graham Nash]

I had the cover off my boat during the recent heavy rains and my fuel tank was submerged in rain water.

 

I am sure the guage is higher now than it was when i last used it, so am guessing that water has entered the tank (possibly through the breather cap).

 

Is there any way I can tell, and if there is water contamination is there anything i can do?

[Sinbad]

Graham,

I think the water should coalesce in time and form an oily layer at the bottom, with the clearer fuel at the top. But your pick up is going to be at the bottom of the tank, so dont just run the engine!

Basically, water is insoluble in fuel, but sometimes the water droplets are dispersed very finely in the fuel, form a 'rag' or emulsion and cannot be separated easily, or passing through a hydrophobic/ water sep filter. Most boats have these filters fitted, but they are only for minor quantities of moisture.

 

I dont know if its recoverable, or if you can skim the good fuel off the top, but it seems a bit doggy running it through your engine when you rely on it to get you home.

 

I'd probably blend it off with the fuel in my wifes car, and not tell her!!!!

 

 

Paul

 

 

 

 

[Graham Nash]

I dont know if its recoverable, or if you can skim the good fuel off the top, but it seems a bit doggy running it through your engine when you rely on it to get you home.

 

Paul

That was my thoughts too

[petesnr]

You could probably siphon off some clean petrol from the top but would hesitate to use it in a boat due to safety reasons.

 

For general information, products such as Fuel Set contain detergents which break up water in fuel systems into such small particles that they pass through the engine harmlessly but this would not work for large amounts of water at the bottom of a tank.

[Rob]

 

Neal - had some pads that soak up fuel or water - can't remember - he might be able to help.

[Jim]

Can you pick the tank up ?

If so, tighten your cap and breather.

Lift the tank and stand it upside down on something ( workmate bench )

with the breather at the lowest point.

Leave to stand ( an hour or so ).

Place container under breather and loosen breather.

The water should be at the lowest point, so when water stops, and fuel starts to flow - - you should have cleared the worst of it.

 

Otherwise, use a long syphon and suck from the lowest point in the tank.

 

 

Jim

[duncan]

1. syphon it all out into containers

2. refill with fresh - and add a bit of fuelset

 

if you can salvage the old stuff for use in a mower then fine - I wouldn't put it anywhere near a boat or car engine unless I was absolutely sure it hadn't actually been contaminated in the first place.

[Graham Nash]

1. syphon it all out into containers

2. refill with fresh - and add a bit of fuelset

 

if you can salvage the old stuff for use in a mower then fine - I wouldn't put it anywhere near a boat or car engine unless I was absolutely sure it hadn't actually been contaminated in the first place.

i think this will be my course of action. Dont want to bugger 7 or 8 grands worth of engine for the sake of

[Mike Fox]

Might be a silly question, but how do you get rid of 50 litres of petrol safely, if you don't have a petrol mower (or a m8 with one)?

 

Burning it would hazardous, and oil collection points wouldn't touch it.

 

Would the RAC or AA be able to find someone to shift it? People put wrong fuel in their cars, and am sure there's an "extract and clean" service they could put you in touch with?

 

Mike

 

[duncan]

I thought we were talking about a bit less than this - if it's 50l then I would probably put is somewhere to settle out for a month, then siphon off 40 of them very carefully. Add some Fuelset and then further dilute/mix into the car when refilling over time.

 

with care you should get another 5 for the mower - but I agree that even the last 5 is a lot of petrol to get rid of - burning is definitely not a sensible option (as it tends to explode as you know!).

[great white]

Perhaps a PM to niggle may be a good source of advice on this one.

[Coddy]

Just to add fuel to this thread (pun intended)

 

Did you know that in most car fuel tanks you have bare wires attached to terminals actually in the petrol.

 

I know it is only 12v but I would have thought that the petrol would have made a short circuit but obviously not as I discovered when helping my son change the electric fuel pump in his car.

Of course it is the fumes that is highly volitile but I could not get over the use of crimp connectors covered in petrol!

 

Dave

[gaffa]

Thought I'd hijack this oldish thread as it is still valid.

 

Just had another bout of contaminated fuel (Petrol) in my 100litre stainless steel fuel tank.

 

This is becoming a serious issue as all evidence points to Ethanol in Fuel problems

 

Before I elaborate I realise that I am more prone to these isssues as I use my boat very rarely so it sits on a pontoon mooring with very little (if any)agitation of the fuel in the tank

 

 

I had a similar episode about 9 months earlier which meant I had to get rid of about 80 litres of fuel and replace filters etc etc but thought water was entering the tank via the filler cap or the fuel tank level sensor housing and these were investigated and replaced as necesssary.

 

However since the last episode just over a month ago and costing me around

[Ian.Jones]

I do not profess to be an expert, but I have some experience.

 

All bio-fuels are hydroscopic (attract water) and this is an increasing problem as bio-mix ratios have increased, particularly where fuel tanks are standing for extended periods. The old advice of keeping tanks topped up to prevent expansion/contraction sucking in damp air, has to be weighed against hydroscopic contamination. I doubt whether there are many places that you could now buy petrol or diesel without some biofuel content, except speciality fuel supplies for vintage cars at prohibitive prices.

 

I have a boat in Spain which is left for six months over winter, and we now leave as little fuel as possible, well dosed with biocide, topping up with fresh fuel at the start of each season.

 

For your tank to have over ten litres of water in a 100 litre tank over the period of time indicated, would suggest that water is getting in somehow. 10% sounds too high for hydroscopic action alone.

 

The most likely cause would be the rubber seal on the fuel cap. Often these are not fuel grade rubber, become contaminated with fuel which causes them to swell, which in turn can allow water ingress. I'd start there, and then look for other causes.

 

I hope this helps.

 

Ian

[Rob]

10 litres of water off of a measured amount of 50 litres of fuel, seems an awful lost as Ian says.

 

Obvious answer is.........measure the amount of fuel left in the tank accurately (assuming the 10 litres is an accurate measure of the amount of water removed), if you're left with 40 litres of fuel, you are correct that is is an ethanol issue, if you still have 50 litres of fuel you have a water ingress issue, simples I think!!!

 

Hth,

 

Rob

[gaffa]

The most likely cause would be the rubber seal on the fuel cap. Often these are not fuel grade rubber, become contaminated with fuel which causes them to swell, which in turn can allow water ingress. I'd start there, and then look for other causes.

 

This was my first point of call when I had the original problem and the rubber seal was changed .There was no tell tale evidence of water getting past the replaced seal even if I played the hosepipe on the cap having first stuffed kitchen roll in the filler pipe . I will retry again tomorrow just to reconfirm.

 

The only other way in is via the tank vent but this is a proper fitting and angled slightly on the hull It is very unlikely that large amounts of rain water can find its way in although it is the ideal route for hydroscopic absorbsion from the very wet atmosphere we have been experiencing recently.

 

Bilge is dry, Fuel Tank surface is dry and it is fresh rather than salt water that is being collected.

 

Obvious answer is.........measure the amount of fuel left in the tank accurately (assuming the 10 litres is an accurate measure of the amount of water removed), if you're left with 40 litres of fuel, you are correct that is is an ethanol issue, if you still have 50 litres of fuel you have a water ingress issue, simples I think!!!

 

Good suggestion Rob ....Only problem is where do I store 40 litres of fuel?....Looks like I will have to buy more Jerry Cans I already have 2 filled with fresh fuel I was going to top up with today.

 

The Guys From Holes Bay Marine were saying they are seeing a lot of fuel separation /water contamination issues currently and also thought it was due to the ethanol content of the fuel .and the fact that I am not using the boat often enough ......I WILL GO THROUGH THE FUEL SYSTEM WITH A FINE TOOTH COMB TOMORROW AND HOPE I CAN FIND A WATER INGRESS POINT ....

 

Alternative is to pay someone to take the boat out at least once a week....any takers??

 

Thanks For the advice guys.

 

Peteg

[Rob]

 

More cans Pete!