I have been running B99 Bio-Diesel for the past year or so and it has worked great. Recently I noticed a small leak underneath the BJ70 which looks to be coming from one of the fuel lines. Turns out Bio-Diesel is a really good solvent and will eat up older rubber fuel lines.

I did some "Googling" and found Zander's Bio Diesel Conversion Page which described in detail the process of replacing the old rubber fuel lines with viton fuel lines and repriming the fuel system.
Good stuff! Now I am off to Napa Auto Parts.