I am dealing with a kubota d1105 that is losing prime running and exhausted all paths I can think of past replacing the IP. I started by replacing both the feed and return line along with both filters, this solved nothing. So I pulled the mechanical lift pump, there was no sign of leaking into the crank case and pumps up fuel fine to the main filter. After casing my tail some, I replaced all clamps with ones that would get tight such that cant twist them on the fittings. Seeing nothing so far, I pull the draw line back out the tank to check the somewhat new pick up and was not clogged. Not seeing nothing wrong with the feed, I went chasing the black smoke issue and that was not the source. It involved pulling the injectors and pop testing them to find one that was low with a slight dribble, so was replaced it. So the the black smoke is solved and only hint of blue here and there. With this issue not making sense by now, I put a electric lift pump on to rule out a wore out lobe for the other pump. This primes the system up easier but air is still replaceing the fuel in the main filter. Where do I go next with finding the source of the problem?
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