Starter issue?

I have a question concerning my 1947 KB1 I hope someone can help me with. Upon returning June 1 to North Dakota from my winter home I started up my KB1 and ran it on 3 different occasions over the next week. The most recent time was yesterday, June 12th when I drove it about 9 miles to pick up take out food at a local dining spot. After shutting the vehicle off, picking up the lunch order and returning to the vehicle when I depressed the starting pedal nothing happened. I checked all the wiring as well as the battery connections and all looked fine. I then pushed down on the motor switch located on top of the starter with my finger and heard a whirring noise, climbed back into the cab, and again pressed down on the starting pedal. The starter engaged and the vehicle started up and I was able to return home. However now the starter won't engage, nothing happens when I push in on the motor switch or when I press the starting pedal. Do you think I need a motor switch, new starter or both. Thanks in advance for your feedback.

Switch could be fouling up... Also check to make sure that the bolt at the top of starter didn't fall out. It is the v shaped hammer that hits the starter button and engages the gear. Just in case the nut vibrated off...

Thanks for the advice.

Switch could be fouling up... Also check to make sure that the bolt at the top of starter didn't fall out. It is the v shaped hammer that hits the starter button and engages the gear. Just in case the nut vibrated off...

^^^agreed^^^
And sometimes starter drive gear is lined up exactly with a flywheel tooth and won't engage.

I sometimes have to stomp the plunger a few times to jar it past or manually push button to spin starter so it clears, that MAY be your problem, it is common on these trucks