Fuel Bugs

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Derik

Senior Member
Joined
Aug 21, 2018
Messages
160
Location
United States
Vessel Name
Pearl Grace
Vessel Make
Marine Trader/Sun Deck 44
On my last filter change I treated my fuel (about 250 gallons) with a biocide to kill diesel bugs. I also changed the o rings for my fuel caps.

Since the treatment of biocide I have used the boat about 5 hours, with lots of back and forth and rocking. The other day I drained the fuel bowl to see how bad the fuel was sitting in the bottom of the glass bowl. I poured this diesel into a glass jar and examined it. It was full of little black specks which I think are the bugs or their waste or even possibly sediment. The condition is worse now than before the treatment.

Has anyone here been through this drill? Is it a matter of a lot of Primary filter changes in order to get to the clean fuel? I am guessing all of the bugs end up at the bottom of the tank. I have the site tubes on both tanks and that fuel looks good.
 
Are they bugs or asphaltene? What made you think you had bugs? Next time, maybe post a picture.

Ted
 
The last filter change my primary filters had slime on them and looked really bad, and I have had black specks in the fuel bowls just much more now after the treatment.
 
I have heard that if you have "bugs".... that after a treatment expect to change filters frequently for awhile.
 
Yeah you killed the "bugs" as they are refereed too. This could cause your filters to clogged. I change and clean my filters and housings once a year to prevent clogged filters. If you get a lot of bugs, you may want to have your tanks cleaned.

Regular maintenance is the key.
 
Black specs sound more like ashphaltene which is degraded diesel fuel.

Actual bugs would more likely produce a slimy mess in the filter.

You will need to be prepared to change filters a number of times untill the stuff has washed through.

I agree about a few photos may help get some opinions.

Just a suggestion is to ensure that water is not getting into or onto the tank. That will promote "bugs" whether you have them right now or not plus damage the tank itself.
 
If the problems is bio fouling. And you treated with a biocide. You will be changing filters regularly for a while. All the dead "bugs" are in suspension and need to be removed from your fuel. Been there.
 
Bugs only live where there is water in the duel.


Do you also find water in the filter bowl?
 

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