64 Dart Starter Problem

When I try to start my 1964 Dart, I hear the solenoid click, then the starter just spins without turning the engine. Can anyone tell me what's wrong?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.