The solenoids have the same threads as the old bowl bolts so the easiest test is to get a bowl bolt & swap them.
Without the solenoid you will have to throttle down to a low idle before you shut off or you will get a big after fire from the muffler.
That is throttle down then shut off.
Do not wait for excessive amount of time because the engine tends to overheat when running at a low idle after being used at full throttle.
The other alternative is to fit an inline tap up stream of the fuel filter or pump.
The position is not important but if it is upstream then you can shut down the fuel supply when changing, pumps or filters or cleaning the carb.