Here's the situation:
1987 300 SDL dormant for the last 6 months (had been running on biodiesel). Replaced fuel lines and primary and secondary filters. Unscrewed injectors and they were gunk-free and wet with fuel. Pumped out a mess of air. Now, he starts but runs for 1-4 minutes before, well, pooping out. Could it be...
1. Old fuel? It had biodiesel sitting in the tank and the fuel lines we removed had some of that bio cholesterol stuck in there.
2. Fuel pump (pardon my ignorance, but do I have a fuel pump?)
3. Bad karma?
4. Some air leak I haven't thought to seek out yet?

Any advice y'all have, I'd appreciate! Just can't figure out why it starts, idles for a while and then dies...

Thanks a lot!