Buying a boat with old fuel in the tank?

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ds797

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Hello :)

I've been offered a fairly decent deal on a 35ft sport cruiser in Spain. It's not had much use in recent years but is in very good condition.

My concern is that the remaining (circa 50%) diesel fuel in the tanks dates from 2013. Yes, 2013.

The engines (Volvo d4 260) have been serviced, and the rest of the boat is mint.

Any thoughts on potential diesel bug? (remember its in Spain not UK)

What would you do if you're buying this boat?
- Risk the fuel being ok?
- Have the fuel "polished"?
- Add fuel treatment? Which?
- Scrap the fuel (responsibly and legally), clean tank, refuel?
- Something else?

Thanks :)
 
At that age of diesel I would get it pumped out. It may well have separated out and left a gunky layer on the bottom.
Diesel bug is likely in any boat in the Med, it's warm. So I would have it all pumped out and the tank cleaned as well as it can be withount making big holes in the tank and see how it goes from there. Tank cleaners often have cameras they can put into the tank so you can have a look.
 
My starfisher came from France and had a load of crap in the bottom of the tank, which I found out on my maiden voyage. I had access panels cut into the top of both tanks, then the fuel was polished and the tank cleaned. Never had an issue since. It’s well worth the money to do and in the grand scale of things, not a huge expense
 
Get rid of it by pumping it out.
Then give a new delivery a strong shock dose of Marine 16.

When we had our case of the bug, I decanted about a gallon of slimy stuff into a clear container from the bottom of our tanks.
Hit it with some Marine 16 overnight and in the morning the contents of the container were clear.
So, dosing with a strong dose of Marine 16 should get rid of any nasties.
Loosing that half tank of old fuel is a small price to pay for a nice clean fuel system.
 
nortada said:
But make sure you have plenty of replacement filters.

Stick some biocide in the tank before running. Amazon.co.uk : wynns fuel biocide

Does the tank have a drain-off tap at the bottom of the tank? If so you can remove the gungie fuel from the bottom of the tank.
Click to expand...

the fuel will get 'polished' this way as spare fuel to the engine is returned to the tank
 
Thanks for the advice, will check the tank for drains. I'll get a quote for pump out and safe disposal.

Intrigued by the idea of just running it and having plenty of spare filters....

Is it the case that the reason the engines would stop would be blocked filters? If that's the case then I can have loads of spares.

Also it might be an option to run the engines but have a couple of spare diesel jerrycans with a facility to pump this diesel to the engines in the case of the main tank being contaminated?

Thanks.
 
If you had a pair of older all mechanical engines, I would suggest topping up with fresh diesel and diesel bug killer and see how it goes.
However you have modern D4s with very expensive injectors etc - so I wouldn't risk it.
 
Can you get access to the top of the fuel tanks? If so see if you can remove the fuel gauge sender unit then use a vacuum oil change pump and suck several litres of fuel from all around the base of the tanks. Decant this into a clear container and you will get an idea of what you are dealing with. Old diesel won’t go off, you only have to worry about water, rust or bug. If you can drain any contamination out then dose it, see what’s available I use marine 16. Would you be able to test and check before any journey? If so take the cautious approach, check clean and dose. If it looks really bad then call in a fuel and tank cleaning company.
 
In the UK and if you had somewhere to store it.
Would pump out that fuel into 20 litre drums and let it settle for a while.Weeks/months.
If its as clear as a bell with no visable contamination, water or debris, pop it back into the tank a small amount at a time.
 
As well as diesel bug I would be concerned about the condition of the fuel tanks if they are metal and especially if they are aluminium, due to water sitting for years under the fuel resulting in internal corrosion of the tanks .
 
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