Possible the stator has encountered a meltdown, and if so, it's dripping a sticky looking substance down on that nylon bushing area... or somebody greased that white nylon bushing and that collects debris which causes binding.
At any rate, you need to remove the flywheel, stator, and the timing base. Clean the timing base and the nylon ring thoroughly. When assembling, slightly grease only the brass bushing... and use only a coating of oil on the white nylon ring.
If the timer base has a tendency to stick when you re-tighten the small screws on the retaining clamps, simply install a very thin washer under the offending clamp.