In my previous boat, I had a similar issue with the feed tube getting clogged with some sort of sludge. Three expensive supposed Diesel mechanics, I mistakenly hired, were clueless about the cause of the clogs. Finally, I figured out, myself, that the problem was was significant bacterial algae growth in the fuel tank. Not really a stroke of genius on my part, since the supposed Diesel mechanics had replaced nearly everything else in the fuel system. At that point, there was nothing else left to fix!
The kicker? It turns out that algae growth in fuel tanks is actually a very common problem in older Diesel sailboats.
The fix? I had the fuel tank power spray washed for $100. I could have replaced the fuel tank for slightly more money.
That solved the problem. No more feed tube clogs. In retrospect , it should have been obvious to me that a dirty fuel tank was the problem and even more obvious to the supposed Diesel mechanics I hired. The lesson I draw from this is that many who claim to be Diesel Mechanics are not competent.
