Biofouling in fuel line

[ffelker]

The fuel line from my tank to engine compartment - about 10 m long - is severely fouled. Fuel will not flow. Any ideas on how to clean it out?

[BillKny]

ffelker,

No details will get you no answers. Try answering these questions as see if you get more help:

• What kind of boat?
• What kind of fuel?
• What size line?
• What is the line made of?
• Can it be removed?
• Are there any filters, valves, pumps, elbows, etc, in the line?
• How long has it been like this?
• what caused the problem in the first place?
• Has anything been tried and failed?
• Anything else you can think of that might be useful to someone making a recommendation?

[thinwater]

Blow it out with compressed air? Then re-prime.


Otherwise, it probably has to come out. Obviously, when finished you want to clean the tank and shock treat the whole system with biocide. Obviously, the bugs went right through the filter.



Yup, been there, not that unusual in boats or in industry.

[Uncle Bob]

Further to the advice above, is the problem biofouling or asphaltenes?

[ffelker]

Replies are below - thanks!

Originally Posted by BillKny

ffelker,

No details will get you no answers. Try answering these questions as see if you get more help:

Replies below

• What kind of boat? Outremer 51
• What kind of fuel? Diesel
• What size line? 8 mm ID
• What is the line made of? flexible fuel hose - rubberish
• Can it be removed? only by tearing the whole boat apart
• Are there any filters, valves, pumps, elbows, etc, in the line? no - I have isolated the problem to this line
• How long has it been like this? Hard to say - 6 months at worst
• what caused the problem in the first place? Biofouling in fuel tank
• Has anything been tried and failed? Tried blowing the line out with a hand air pump (like used to inflate fenders)
• Anything else you can think of that might be useful to someone making a recommendation?

[ffelker]

No problems on the port side - only on starboard side, so not bad fuel. Biofouling is visible in samples taken from the starboard side but not the port side, so unlikely to be asphaltenes.

Originally Posted by Uncle Bob

Further to the advice above, is the problem biofouling or asphaltenes?

[ffelker]

Tried using a hand pump (like used to inflate fenders). Will try again with higher pressure compressed air. Thanks!

Originally Posted by thinwater

Blow it out with compressed air? Then re-prime.


Otherwise, it probably has to come out. Obviously, when finished you want to clean the tank and shock treat the whole system with biocide. Obviously, the bugs went right through the filter.



Yup, been there, not that unusual in boats or in industry.

[Uncle Bob]

Originally Posted by ffelker

No problems on the port side - only on starboard side, so not bad fuel. Biofouling is visible in samples taken from the starboard side but not the port side, so unlikely to be asphaltenes.

Given this then I would suggest a heavy dosing of a product designed to combat biofouling, flushing the fuel line, first with compressed air then fresh fuel followed by a rigorous fuel polishing. This should remove the problem and from a maintenance perspective a regular polishing and dosing each fuel fill should eliminate any further problems.
There are a number of threads here that describe fuel polishing systems and processes.
All the best.

[Scubaseas]

Nylon wire snake might work? If not put some biocide in the hose and let it soak then blow out with compressed air.

[Scubaseas]

Weed whacker/Strimmer line would also work as a mechanic aid come to think of it. Depends on what radius bends you have. If you have 90* bends that may be your problem i.e. the hose is collapsed on itself. See this all the time on boats.

[sengland]

Originally Posted by ffelker

The fuel line from my tank to engine compartment - about 10 m long - is severely fouled. Fuel will not flow. Any ideas on how to clean it out?

If your fuel line is bio-fouled then probably your tank is also. There are fuel additives to prevent bio build up. Maybe the instructions include a heavier dosage that will shock remove the build up but I don't know. Easiest way would be to replace the fuel line.

[dadster3]

I dunno. From what you said it seems to me that replacing it would be the easiest and cheapest. Plus you get a new line that you won't have to worry about for a long time. Throw in a couple of new hose clamps. Take the old one off and take it to West Marine or another local marine dealer to match it.

[thunderhoof]

I had the exact problem a few years ago in an older boat. I saw no practical solution except to remove the old hose at the tank, pump out the grey, gritty mess in the bottom of the tank and to replace the fuel line and fuel filter at the engine. Note that the sediment collected along the 8 ft horizontal run of the fuel line which is after the primary fuel filter. After that I religiously added Biobor JF every time I fueled.

[Djarraluda]

Originally Posted by Scubaseas

Weed whacker/Strimmer line would also work as a mechanic aid come to think of it. Depends on what radius bends you have. If you have 90* bends that may be your problem i.e. the hose is collapsed on itself. See this all the time on boats.

Better than this line, try for a length of plastic spaghetti - the plastic wall plugs stuff that you cut to length, except I would try the whole spool. I think it comes in 5m rolls at the hardware stores, it's diameter will do more cleaning and the more rigid nature will allow you to push it through better than the streamer line.
Roger

[jamhass]

Just replace the line. When doing so, connect the old line to the new line (using seizing wire not hose clamps -- they are too large) and use the old line to pull the new one through the boat.