How do you check the fuel solenoid on Briggs 18 hp ohv engine?

Switch the ignition to on. Put your meter to 12VDc. Touch the hot wire going to the solenoid with the meter positive probe . Touch the meter negative probe to ground. If you have 12VDc and you don't hear a click when you turn on the switch, the solenoid is probably bad. If you don't have 12VDc, check fuses and the wire going to the solenoid.