[Rick Parker]

I had this happen recently, it was slow to return and sticky. I had not serviced the distributor in 4 or 5 years other than occasionally replacing the cap & rotor. I have had an upper radiator hose burst but never felt (or thought) it necessary to check for moisture inside the cap. I removed my distributor and squirted some carb cleaner under the upper pivot plate until it was moving freely, then gave it a little WD-40. The corrosion issue we face is caued by moisture condensing inside the cap. During the off season I am either going to remove the cap or the distributor entirely.

Gasses from within the crankcase are forced up into the bushing clearances of the shaft AND that of the assembly the reluctor is attached to. Things get gummed up. If your particular engine has significant blow by, this gummed up issue will be more pronounced.