Fuel Additive/Fuel Tank Polishing

[Keith Giller]

Just did my annual maintenance and my 10 micron filters were BLACK.  Obviously I’ve got some algae in the tank.  Any recommendations on an additive?  A biocide like Bioguard? Anyone ever do the fuel polishing?  I’m assuming they just run the fuel through a filter and not really clean the tank.  Any thoughts would be appreciated. 

Topic

[David Amble]

Riv 43 – fuel polishing setup

Years ago, I had a Riviera 43 (99 model) and set up a fuel polishing system as per the attached photo.  Basically two 3-way valves and a circulating pump.  Also, I once had the opportunity to see inside the fuel tank of a 43 (someone else had cut one open to make it larger) and I noticed the fuel supply came from the forward bottom of the tank and the fuel returns had internal pipes leading from the forward top of the tank to the aft of the tank, so there actually quite good turn over of the fuel when polishing.  I did not have problem with fuel but installed the circulation system as basically something to do.  My current boat (Riv 51) has a forward long range tank and I am able to ‘batch’ filter the fuel from one tank to the other if need be.

[Clark Leighs]

I should have added take a good look at the filtering to allow for catching  and consider adding  vacuum guage with a tell tale needle so you can monitor the rate of filter plugging so you are less likely to be sirprised.

[Clark Leighs]

Black on the filter?     THat sounds like Ashphaltene,  not algae.     

Ashphaltene is a natural product of the diesel fuel degradation or breakdown.   It turns very dark to black.

 

For ashphaltene  you need a fuel stabilizer rather than  a biocide.      THe other way to combat it is to use the boat and burn the fuel so the fuel does not stagnate for long times.

 

Typically what you are referring to as algae is actually not. Algae is plant life and it needs light.    That type of  contamination  is actually microbes which  use the diesel as food living at the interface between the diesel and water in the tank..    THey create a slimy, stringy mess , not a black coating and the colour is quite different, lighter and mottled.

For either you will need a good supply of filters and pay attention to Neto’s suggestion  about filtering.   

Just in case be sure you don’t have any water in the tank.   Frequent sources are poorly sealed deck fuel fillers.,  lack of  O rings or O rings in poor shape  at the  filler cap.  The  O rings need to be changed every few years, 2-3, and they and the threads should be greased.  Not gobs of grease but a thin coating including the threads.  Also be sure the deck fills themselves are properly sealed to the deck.

 

 

 

 

 

 

 

1 user thanked author for this post.

Edwin Harvie

[Neto]

I use Biobor JF but probably the best thing you can do is follow Tony’s advice on fuel filtration here on the site. It uses mud filters before your racor filters.

[Author]

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