Fuel YTS 4000 Fuel Question

I got a used YTS 4000 24hp 46" mower last year & have never got it to crank reliably.

Tractor # 917.289283 with B&S Platinum engine model 445677-1188-B1. I suspect a fuel problem.

I know the solenoid valve at carb opens & closes with 9v. I replaced the fuel pump & fuel filter.

When I remove the fuel line at the carb & turn the key, there is no stream/dribble if fuel coming out of the hose.

I don't understand why.

Any advise is appreciated...

Bill