Bleeding the fuel system will purge air from from the fuel line so the engine can draw it in. Older tractors use a bleeder valve system to accomplish this. The BX-Kubota's use a small fuel pump to deliver fuel to the engine.
When system needs to be bled:
When fuel filter or fuel lines have been disconnected or removed
When the fuel tank is completely empty
Before using the tractor if it has not been operated for an extended period of time
How to bleed the fuel system:
Fill fuel tank
Turn key to “On” position for about 30 seconds. (Allows fuel pump to purge air from system)
Start engine and let it run for about 30 seconds, then turn it off.
