Regarding the slow crank issue... check grounds and clean. Using a dielectric grease will help ward off corrosion.
Also, pick up a few commutator stones. Some places will sell individual, others you gotta buy the box of 12. About $30 last time I got a box. Measure the frame and buy the stone size that will fit in the frame cut outs.
The copper on the commutator will oxidize and cause a problem. Esp. in starters that don't get used much. One of my annual pre-driving season PMs is to clean the starter and genny commutators to remove oxidation. Then normal starting/driving keeps them clean in the summer.
