Blocked diesel supply pipe

[KenMcCulloch]

After the 100 mile delivery voyage that brought Border Maid north of the border I went to change the primary filter, the water trap being full of nasty looking brown stuff. Replacing the filter element was straightforward but imagine my surprise to find that fuel would not flow into the filter. It's well below the tank so it should just be a matter of opening the fuel cut-off valve and opening the bleed screw. No diesel action whatsoever.

I tried fill the tank which was only half full, still no joy so took the inlet hose off the filter and found nothing coming out. various sucking and blowing from either end eventually leads me to believe there is some foreign matter stuck in there somewhere. It wasn't enough to stop the engine but is enough to stop me from bleeding the system. Anyone experienced such cirumstances with useful advice to offer?

 

[oldharry]

<<nasty looking brown stuff>> ... is the dreaded diesel bug, and you wont get it out of your fuel line without a high pressure compressed air line. Unfortunately it will be in your tank as well, so that needs to come out for a good clean as well, otherwise the next batch will get into the fuel line/ filters etc.

It grows in the interface between fuel and water, so there is water in your tank as well. Apparently all diesel fuel has 'the bug', but it only grows into this jelly like substance if water is also present.

 

[KenMcCulloch]

Thanks oldharry, I understood the cause, I was really looking for advice about unblocking the pipe in the short term.

 

[Clyde_Wanderer]

I agree with Old Harry, and would suggest removing the tank for cleaning. preassure washer will get the crap out.
If there is not an inspection plate on it I reckon you should consider cutting out a large hole and making a plate while the tank is out, making it easier next time.
You might be just as well renew the fuel pipes too, and fit a second filter unit, as I have just done, gives added protection.
One of the most common causes of breakdowns at sea is fuel problems.

 

[Anonymous]

You need to use an air line. I have used an ordinary 12V car tyre pump for that very job but you might need to make up an adaptor. You can be posh and fit a Schroeder valve onto a brass fitting and screw the pipe with olive onto that or you might get away with one of those plastic adaptors for pumping beach balls (you attach the tyre pump to the plastic thingy and stick the plastic thingy into the copper pipe and hold them together). Depends on how badly it is blocked.

Do make sure that it isn't simply that someone has turned a valve off - as happened to me once /forums/images/graemlins/blush.gif

If you have diesel bug then drain the gunge from the bottom of the tank and use one of the additives that emulsify the water - I checked them out and decided that Fuel Doctor is the one to carry for both diesel and petrol as all it does is to emulsify the water, and that's what you want to do /forums/images/graemlins/smile.gif. Make sure that you find out where the water is getting in and if you find that it is just condensation and age, make sure you can draw a few ccs several times a season from the bottom of the tank. The cost of equipping a drain in the tank will be far lower than the cost of additives long-term and is far more effective.

 

[gianenrico]

VERY silly opinion: check the "Emergency fuel cut-off valve" is not turned off. This device often has a string type command which is led, typically, in the dinette or stern cabin AND WORKS ONLY IN CLOSING: reversing the position of the handle to the "OPEN" position in these locations DOES NOT actually open the valve at the tank. You have to reach that valve and set it properly.
Plus cleaning the pipe.
Hope it helps .
Cheers

 

[2Tizwoz]

A valve followed by a primary filter next to the tank incorporating a see-through bowl and water separator with drain lets you monitor the condition of your fuel system permitting a bit of maintenance before troubles arise.

Sometimes there is a filter on the end of the draw-off pipe inside the tank which is not easily cleaned particularly at sea and could be eliminated as it only protects the pipe.

 

[KenMcCulloch]

Thanks for the suggestions, sensible and otherwise. I have sourced 5m of new fuel hose for a fiver and on the basis that once I have taken the old lines out I may as well replace as try to clean them out will be fitting new sometime during the week. Removing and cleaning the tank while afloat is not very practical so I am going to suck the bottom layer of what we Scots call 'keech' (guttural ch) out with an oil change pump and dose it with chemicals. A large supply of primary filter elements will be kept aboard. I'll let you know how we get on.

 

[Anonymous]

I was thinking about copper fuel line not 'hose' when I suggested an air line, of course

 

[ms1]

I had simultaneous twin engine failure wth chronic fuel bug. Blew the pipes back with a 12v dinghy pump and vacuumed out a huge load of muck from the fuel tank (via fuel sender hole) with a long plastic tube (a la Homebase) and one of those hand suction pumps into some 5 litre mineral water bottles. In the longer term I had the fuel tank removed and cleaned, although it was suggested that as I had removed so much gunge I might have then tried an additive. Main reason for not doing so was that my 'vacuuming' around that tank was in the section that I could access and I had no idea what was behind the tank baffles. I know someone who used one of those " we come to your boat and clean your fuel for you" services .. I am very glad that I didnt