[Richard and Rhonda]

Ok, it's fixed. I did not have to tear anything out to get to the motor. The problem was that there is an arm that attaches to the motor, and the arm was loose. The arm is part of a mechanism that converts the rotational motion of the motor into back and forth rotation. The arm is splined onto the shaft, and tightened with a nut. The nut has yellow paint on it in the photo.

The reason the arm is loose is another story. One of the two shafts on the front mounting plate is a dummy shaft. Both of mine were practically siezed, and the picture shows why. I cleaned them up really well, greased them, replaced the sealing o ring, and circlip. Works great now, but those dummy shafts have a lot of side load on them, and I will be looking for a replacement shaft and bushing. The shaft was originally chrome plated, and the bushing looks to be bronze or oilite. I was able to press out the old bushing, but I could not find a replacement locally. The shaft is sealed by an o ring with a washer on top. There is a circular clip that slides into the groove to hold the arm in place. I bought replacement o rings and clips at Home Depot