Diesel Bug

[Ronar M]

Hi All

I reckon the root cause of Ronar M’s recent engine troubles was diesel bug. The lift pump was clearly on its last legs and dragging fuel through all that gunge was the last straw. So now she is running again, I would like to treat the tanks and I wonder if anyone has any experience of the proprietory brands of diesel bug killer and which they would recommend.

I have pumped out as much of the gunge from the bottom of the tank as I can. Now I want to kill off the bug before having another clear out of the tanks once winter is upon us.

Cheers, Trevor

[Moderator]

Hi Trevor –

Practical Sailor (US magazine, check http://www.practical-sailor.com) had an excellent article on biocides in July 2009 issue. They performed tests to determine which biocides did the best at killing their two different cultures of “bugs”. They also have a good explanation of what the “bug” is.

The article found that different biocides have varying success rates with their two bug cultures. So, they recommended that you pick two of their recommended biocides, each of which effectively killed one of the cultures. Then alternate biocides at each fill.

They recommended these that killed their “culture a”: Star Brite Biodiesel and Valvtect Bioguard. These killed their “culture b”: Biobor JF, Racor Biocide. In the article they show the complete results, which are interesting.

After reading this article, we chose to alternate our use Valvtect and Racor biocides. (In fact, Valvtect marine diesel fuel is available here in the US, which already has the Valvtect biocide included in the fuel.) We have used this combination for about 15 months, and not had a problem (maybe we would not have had a problem anyway, but we are currently running on old fuel we obtained last October and still have about 1/2 tank left).

Last year, we had our tank professionally cleaned and then installed a dedicated fuel polishing loop in hopes we never again will need to clean the tanks. Maybe that was overkill, but we don’t want to experience what you’ve just gone through. (You can read about our cleaning experiences hereand the dedicated fuel polish loop here).

Congrats on getting your engine working again.
Marilyn

[Happy Dolphin]

fit a T piece on fuel inlet side of injector pump conect a vacume/presure druck gauge and constantly monotor your system usuual is 2 to 4 lbs psi
vacume is fault

[Author]

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