I have a 463 with the 3 cyl kubota engine. Lots of mech skills but not much diesel exp. This machine has about 500 hrs on it. It was running normally at about 1/2 throttle when it suddenly started running very rough and quit. Immediately it would not restart, I thought it was out of fuel. It turned out it was not out of fuel. After sitting a few minuites, it will start up and run/sound normal about 3-5 seconds then shut off. Immediate cranking the engine gets no attempt to start but produces noticeable black smoke from exhaust. Let the machine set a few minutes and again it starts/runs for a few seconds and shuts down and then wont start with black smoke coming from exhaust while cranking. I changed the fuel filter, bled it it out, bled the bleed screw on the injector pump and pumped the primer bulb over and over. The primer bulb never really gets hard but is firm to squeeze. Pulled out the fuel pickup tube from the tank and it is in tact, I see no issues. pulled the return line from the tank that comes from the last injector and fuel flows from it when you squeeze the bulb. Pulled the air cleaner, no issue and will not run without it in the canister. I can feel and hear the fuel shut off solenoid clicking hard when the key is turned on. I believe the engine is getting fuel due to the black smoke. If this were a gas engine I would say it was flooding out due to the engine starting after sitting but the engine runs smooth for the few seconds it runs. I find no emergency air cut off on this engine. The intake pipe runs straight from filter housing to intake. Ideas? Thanks in advance for your help!!