We own a newer Kubota tractor L3130 with a 3cyl Diesel. I replaced a rubber fuel line and bled the system using the wheel/bleeder. The tractor seemed to be missing and was down on power, especially under load. I decided to further bleed the fuel lines individually off the pump by cracking the fitting loose and cranking the motor to make sure each cyl. was getting fuel and all are but now it produces thick black smoke. I called a dealer and they said underneath the fitting I cracked open there are FUEL DELIVERY VALVES and its possible the valve turned when i loosed the fuel line. I attempted to adjust the valves by turning them but by only 1 click in either direction its low on power and missing with no smoke, or runs smoother but with huge clouds of black smoke as it may be getting too much fuel. Im stumped. Any help is greatly appreciated. Thanks guys - Steve