Originally Posted by jamesNB

Stubborn? Yes. Bad advice? I doubt it.
Twelve years is a long time to let anything sit. I don't care if it's gasoline, Diesel Fuel, or asphalt. Drain all the fluids, including the fuel. Eliminate it as a variable. What is it going to hurt?
Surely you know bacteria and algae aren't the same creatures? Nonetheless, if there is or was crap growing in the tank, dead or alive, it will clog the filters. If there were organisms growing in it, surely you realize that has changed the composition of the fuel?
Even if there's no sediment, rust, crust, gunk or water and the fuel is crystal clean, what was put in it last? DF1? DF2? Who knows? It can make a difference.
Drain the tank and clean it. Worst case, it took a couple hours and if it doesn't fire up, you know the fuel's not the problem.
I can't believe you think draining the fuel is "useless". I believe it is common sense.