Diesel tank bug / sender removal

[MagicalArmchair]

We have returned from our little cruise up the East Coast and thought it high time to draw out the very bottom of the diesel tank to see if there was any grime or water. I had purchased a new, clean, little PELA for the job and attached it to some left over copper gas pipe for a rigid probe. I had hoped that the probe would fit down the unused take off, however that proved too narrow, so I undid the sender and sent it down that instead.



On the first draw of 3 litres from the bottom of the tank, I was alarmed to see black gloopy blobs coming up through the pipe. Not many, but enough.



I disposed of that diesel and drew another 3 litres. This time getting less crud up.



I didn’t get a chance to draw more out. Next, I want to put an endoscope down there to check the state of the tank. I’d also like to get the sender out entirely so I can peer properly into the tank.

How on earth do I extract the sender fully? I tried waggling, turning it and swearing at it, to no avail.

Should I be worried? Or should I just draw diesel from the bottom of the tank until it comes up clean, add a shock dose of Marine 16, and the go sailing?

[Yngmar]

How on earth do I extract the sender fully? I tried waggling, turning it and swearing at it, to no avail.

More of those, especially swearing. There's a very specific sender angle and arm angle at which it comes out with sufficient swearing, but it was still bloody tight.

Should I be worried? Or should I just draw diesel from the bottom of the tank until it comes up clean, add a shock dose of Marine 16, and the go sailing?

No need to worry, every old tank has some of that gunk in. That's why you have filters for. Suck up the lowest corner of the tank and let the stuff settle out in a glass. If there's no water in there, no fuel bug can multiply - only then problems arise. Bit of dirt is fine, but water must be kept out of the tank. We do this once a year, the first time about as much dirt as yours came up, following years only a little. I pour it through a paper coffee filter to strain the dirt out and then back into the tank.

Having a nice glass bowl filter helps greatly in seeing if there is an actual problem arising. Some people fit twin filters with a switchover, but personally I think that's best left to motorboats.

Expensive fuel bug treatments are okay to have on board, but only pour them in the tank if you know you have fuel bug (or water to emulsify away).

Keep the o-rings on the fuel filler cap lubricated to keep water out and replace them if they're old and brittle/cracked.

[fjoe]

Is the reddish color normal for Diesel in your country?
In the Netherlands the color is yellowish.
Our highly contaminated Diesel was red (see comparision on picture). The slime of the bugs stopped our engine and we had to be towed back to our harbour.

I recommend having it analyzed (about 50€), and in case of a contamination cleaning Diesel, tank, tubes and filters thoroughly before it will get expensive 

[symphony2]

Yes, in the UK private boats can legally use red dyed commercial diesel. This is often the only fuel available at waterside sites. When we were in the EU our government was in a long battle with the EU over this policy, but of course now not a domestic issue any more. However it may be that once travel restarts and UK yachts visit the EU where the use of red diesel in private yachts is banned, some states (particularly yours and Belgium) may make life difficult again.

I only use white diesel in my boat because I use only 200l or so a year and I buy it at the local supermarket in my 20l containers, usually 22 at a time as I did last week. Never had any problems like yours with fuel bug. Supermarket fuel stations have high turnover so fuel is always clean and fresh. Appreciate this method of fuelling is not practical for others.

[MagicalArmchair]

Thank you all. I will persist with waggling that sender until the little sucker comes out so I can get a clear run at the tank. Great idea with regards the coffee filters to preserve the diesel - it felt wasteful pouring three litres into recycling at every draw.

I’m going to make up a slightly longer probe to make getting to the lowest point easier once that sender has been removed and then try and get up all the crud I can.

If the tank looks clean enough I’ll forgo getting the diesel analysed, I’ll just shock treat the rest of the diesel with Marine 16 just to be on the safe side, then adopt Yngmars practise of drawing a bit each year.

[MagicalArmchair]

I got the sender out! I had to move the "float" arm to "totally empty" in order to get it to come out easily by sticking my finger in the hole .

I couldn't see anything in the tank, even shining a torch in there, and I had left my (rather cruddy) endoscope at home, however, I sucked around the bottom of the tank with my new, longer probe as much as I could and could recover nothing but clean and good diesel.

I threw a shock dose of diesel bug stuff in the tank for good measure and will call that a job done and check that again only when next year comes around.

Thanks for the help!