Good for you!
We had a Potscrubber III fall into our laps two weeks ago.
Filthy, otherwise worked great.
Having done a lot of Potscrubbers through the years (no II, though), here's some stuff I've learned (a lot with the help of the folks around here) which might be useful:
1) That multi-orbital spray arm, even if it were clogged and broken in two and leaking out the sides is one million, billion, trillion times better than the whirligig piece of sh---- which came after.
There is NO comparison.
Now, they do clog and there is a tiny little slit on one side of one arm which tends to clog up, stopping the arm from rotating as fast as it needs to. There is also a thin gasket it's supposed to ride on which sometimes fails and makes screeching noises. If it's failed, just yank the super thin gasket. We have one in use at a friend's house which has cleaned perfectly without it now for 13 years. Better with, of course.
2) The filter cover and the sump pump cover and the cover over the flood-sensor all get filled up with the most horrid gunk over time. They were meant to be cleaned by real enzymes and real phosphate and real chlorine bleach and truly hot water. Too many people used the eco-friendly trash and too cool water and too short cycles these past 20 years. Better unscrew them and clean them thoroughly. Don't put your bare hands into the sump, there's always sharp things in there to attack you. It does need a good cleaning, though.
3) The power-shower arm also gets clogged and, in contrast to what many say who didn't know these units in the old, high water days, it DOES contribute to cleaning, not just removing yibblets from the top rack. The last iterations of this machine are always in cavitation because they don't have enough water to really work well.
4) The one-way valve under the big filter in the back gets clogged. Clean it.
5) Combo52 is, as always, right. You can use a sealant. I've had success (again, running 13 years now with nary a drip) using the blue teflon tape (20x thicker than the usual white junk). It's removable and hasn't crept in those 13 years or five years or on the one we did two weeks ago. Lots of folks don't know there are different PTFE tapes, so they throw them all in one bucket. Of course RTV silicone will work, too.
6) The heating element was de-rated to about 500 Watts from 900 but the design was still for the 900. This means you pretty much have to either feed this machine 125F water for reals or run it at the temp. boost/potscrubber settings for that phenomenal clean.
Remember, it was this series that beat KA dishwashers in cleaning in the Consumer Research tests. They hated admitting it and were not happy to have to do so, but it's true - these dishwashers did the best cleaning job (especially in the corners of the top basket) of any dishwasher ever tested. Runs rings around the current two-drops of luke warm water trash.
You'll love this machine. Many folks will tell you that you must, simply must replace the shaded pole motor. That's one of those religious beliefs. I have NEVER, not ONCE had one fail and I've repaired/cleaned/restored over 30 of them in various Potscrubbers. Not once. I do oil them as GE recommends. Yes, of course the SIEMENS capacitor split-phase induction motors are quieter and run well. Sure, if you must, go for it. But, again, it's a religious objection to shaded-pole, not an actual cleaning ability driven argument.
If you do have to replace the impeller/seal/soft-food disposer, do the whole unit including the drain solenoid. By the time one is done, the other is done, too. The kits are OK if the unit is only 30 years old or so and otherwise in good condition.
So, that's my two cents, for what they're worth. Clean everything, including inside the door and that gasket and the two removable corner gaskets at the bottom. Use the highest heat settings, good detergent and rinse-aid and you'll be totally happy.