Crank but won't turn over

You have a primer on that filter. Reconnect that line & prime the line. All the best. Was there an issue before it not wanting to start now?

 

Just to be clear, it cranks ( turns over) but won’t fire up. Right? Someone posted the same as you did recently, caused some confusion. We know what you mean. It’s obvious.

 

You lost prime now. Pretty sure that’s the fuel line from the tank. Needs to be reconnected, filters primed, primer pumped, and maybe some ether. May need to shoot some air into tank, with a rag over the opening to push the fuel. May or may not need to pinch off fuel Tank vents. It definitely would help. Those stupid primer pumps have never worked right for me. They take a lot of pumping, often leak. But that’s what they’re for, changing filters and running out of fuel. If I remember Correctly, you turn it counter clockwise and pump away.

 

Take the hand primer off there junk probly half your problem

 

The line you have off is the return line to the tank. Put it back on.
Now take the line off above it going into the top of filter base. This line is the return line also but it's before the pressure/ check valve . Crack this line loose and crank engine till steady stream fuel comes out . Tighten line back up and use hand primer till rock hard. Start the truck.