Fuel colour in agglomerator

[Pete-T]

While doing a service on my Beta 43 engine I drained the agglomerator. On opening the drain screw black fuel came out for around a minute, but the fuel in the fuel filter was clean.

Not sure what this means, is it normal as in the agglomerator doing its job or is there a bigger issue I need to address?

[Tony Brooks]

I fear that black may be bug. It might also be the inner lining of rubber fuel hoses shedding. If you can see thousands of tiny flecks, and they feel hard it is probably rubber, if it is all black or slimy bits then it is probably bug.

 

Probably time to drain the bottom of the tank and administer Marine 16 shock treatment.

[Pete-T]

Thanks for the reply Tony,  how is the fuel tank drained ? not sure how the bug has got in as I add Marine 16 everytime I fuel up?

[Alan de Enfield]

13 minutes ago, Pete-T said:

Thanks for the reply Tony,  how is the fuel tank drained ? not sure how the bug has got in as I add Marine 16 everytime I fuel up?

 

If you don't have a drain plug fitted, then its a case of pumping out the fuel, cleaning it, cleaning the tank, then putting the fuel back.

 

Bug generally lives on the water / Diesel interface so you may have water in the bottom of the tank.

 

What sort of fuel filler cap do you have ?

[Tony Brooks]

17 minutes ago, Pete-T said:

Thanks for the reply Tony,  how is the fuel tank drained ? not sure how the bug has got in as I add Marine 16 everytime I fuel up?

 

1. Three are bugs that are resistant to most biocides. We had a member who suffered that, so possibly look for another biocide product. There is a degree of bug in the fuel straight from the refinery.

 

On most narrowboats one uses a length of copper pipe (say 3/8 ish) bent so you can sweep it all over the bottom of the tank via the filler. Fit a length of clear plastic hose to that. Then use that to syphon or pump the fuel from all over until you get clear red fuel.

 

Even if you do have a drain plug it is likely to be at the front of the tank and as boats tend to trim down by the stern it will leave residue at the back of the tank.

Edited November 26, 2023 by Tony Brooks

[JoeC]

17 hours ago, Pete-T said:

not sure how the bug has got in as I add Marine 16 everytime I fuel up?

Which Marine 16 product do you add?

[Pete-T]

Marine diesel fuel complete