Biodiesel and bugs
 

I have a 1984 300CD in which I have been running B100 for over a year and a half. This summer I was out of town and not driving the 300 CD now I am having a problem with clogged fuel filters.
I took the line off to the prefilter and pressurized the fuel tank getting about 3 gallons out that had small black balls in it. I replaced both fuel filters and noticed today a week later that the primary filter is clogging again.
Has anyone else on Bio-diesel had this problem and what did you do?

Thanks for the help!

Are you using rubber or Viton fuel lines?

Rubber will deteriorate fast with B100.

Viton hoses were put on about a year ago.

Biobor or Startron added to every tank will kill them.

If dino diesel (regular diesel) was used for extended periods of time before you switched to bio, then carbon deposits build up in the fuel lines. Biodiesel acts like a solvent and cleans your lines out.

In general, it is recommended to run a blend to overcome issues of rubber degradation. The main thing is probably to make sure your biodiesel is free of water. Depending on the washing process, if water is still in the biodiesel I have heard of bad things happenning if running B100 that has water in it. Lot's of people have run B100 without issues though ... probably lot's more folks on this board that have more/better input than I do on this.

Interesting.... I run B99 most of the time from a local supplier (Glover Oil).

Lately I have been running it in a blend because of all the driving we have been doing. I use the clear style primary filters and noticed them turning black when I started running the Bio in low doses. When it cleared up and most of the fuel lines were replaced I switched to B99 (over a year ago). That is odd. I'm interested to hear the outcome.

Have you removed the screen in the tank (or modified the screen). You said "the fuel hoses were replaced a year ago".... Did you replace the ones under the car at the fuel tank. What a about the rubber gasket at the tank screen.

All the lines were replaced. I also pull the tank screen and clean it. I have pulled the tank screen since and it is still clean even through the primary filter is clogging.
I don't want to pull the tank since this is my daily driver. I will get some startron and see if that works.

I have had this problem.

It sounds like glycerin, or glycerides, coming out of solution in homemade bio diesel. It is often black and insoluble and gets stuck in the primary filter.

I have also seen algae from the tank dissolving in the bio diesel. It takes a while to totally dissolve.

I have about 50,000 miles of B100 experience, but I can't get it any more so I am back to dino for now.

it sounds like algie to me - I've not had my 79 long enough to run much through it - but when i got it the tank was full of algie. The filters had what looked like black sand in them and the bottom of the tank had 3/4 inch of tar like sludge that needed to be cleaned.

I did what I could but I suspect I still have more in there.

In any case - black gunk in the filter sounds like algie to me.

startron tank cleaner, not fuel system conditioner.
and it's a bacteria/fungus, algae requires sunlight.

Where do you find "startron tank cleaner" locally? Is it OK to use with SVO?

Also, I may find this in future searches but will ask now for the good of all:
what is the best method to clean out your fuel tank in the home garage, or the most affordable professional options?

Thanks for any input!

These clogged filters sound like biodiesel dissolving years of coking on the engine and coming back through on the return lines. (As long as its a quality source of bio?) I would start with lesser blends and carry spare filters. That's what I had to do on my 1st wagon starting bio at its 280k mark. What y'all think?

Startron is available at West Marine, either in one of their stores or online. Last time I checked, there was a West Marine store in Raleigh on Capital Blvd. north of the 440 bypass.

I have had a "delayed cleanout" in higher milage vehiclces.

X2 for the delayed cleanouts.

After tuneups , during hot weather, long trips, etc.