Chris, put it appart! the odo is easily remove, once remove you only need to
remove the main needle and the 2 screws, now, watch the main gear that drive
the odo, i bet you that it's loose. Screwing the odo!!!!

This gear is "press fit", it did come loose with age.
Now that you have the odo out, play with the wheel... until you have the
desired millage. It's like "wheel of fortune", or should i say, going to the
 "Casino"........ he he.

Cheers, Ben