I have one of those impulse sprinklers that rotate back and forth clockwise
and clounter-clockwise
The mechanism to make it go clockwise works fine
But when the sprinklers reaches the stop to reverse it's direction
counter-clockwise, the mechanism is stuck and the sprinkler stays at it's
most clockwise position without reversing direction..

A gentle tap on the little arm that contols direction solves the problem
But the sprinkler shoud be able to change direction without external "input"

What are the steps for diagnosing and solving the problem ?
Is there a troubleshooting FAQ or URL for such sprinklers ?

TNX.