Oil & Fuel Kubota running sporadically

[Djhphoto]

I have a Kubota B7500 that is running sporadically. Wether idling or in operation it's not running at full RPMs when I set the throttle. I can see the fuel filter bowl emptying and then the engine cuts off, then the bowl refills to capacity. Any ideas or suggestions?

 

[teg]

Replace the fuel filter first. Other option is junk in the tank plugging up the line.