Check Fuel Quality and Shut-off Valve Clog

What happens here

To diagnose the fuel problem, the creator uses a siphon hose to extract a small amount of fuel from the tractor's tank for visual inspection. He notes that the fuel itself appears clean. However, upon inspecting the fuel cap, he finds significant rust and moisture, indicating water contamination in the tank. He then attempts to open the main fuel shut-off valve located at the bottom of the fuel tank to check for flow, but no fuel emerges, confirming a severe clog in the valve.

Goal: Assess fuel quality and confirm blockage in the fuel shut-off valve.