These types of "automatic chokes" have a bi-metal spring that holds the choke plate closed, as it is warmed up, either by electric or exhaust gas the spring opens and choke plate opens.
Issue with these is you had to adjust them for winter and summer, and for spring tension wear after years of use.
There should be a large black plastic "cap" where the electrical plug is.
There should be 3 slotted screws holding the cap.
Loosen screws and with engine cold, and off, rotate cap so choke plate is just opening
If there are no screws, but there are rivets, they will need to be drilled out and replaced with screws, carb rebuild kits often came with these screws.
In the summer you really don't need the choke for more than a minute or two, but in the winter you will be glad you have it hooked up
Last edited by RonD; 07-22-2014 at 08:11 PM.