The rack actuator is the fuel shutoff. #20 in the drawing above.
Every TL machine I've ever encountered has had issues with the fuel supply becoming restricted.
The bottom suck elbow on the tank and the inlet to the water separator both can collect debris over the years.
If you disconnect the separator inlet and lower that hose, fuel should easily flow out. If not, the elbow in the bottom of the tank is restricted.
If fuel does flow, the separator inlet can be suspect. Full disassembly and inspection of the separator will be required.