In my 30+ years of working on these units I have found that 80% of the problems are electrical. The solenoid consists of two internal coils - a pull in coil and a hold in coil. It may click in but not stay in. I recommend taking it apart and cleaning the contacts, also check that is not full of oil which is common because the seals leak. Take the govenor out and put it in a vise and hook up an ohm meter. Run it up with a drill motor and see if it registers on the meter. I have also found the pin that holds the gear sheared off which will make it inoperative. Of course you could have a cut wire somewhere in the loom, a bad relay, and as previously noted internal mechanical problems. Parts are hard to come by but most internal BW components are shared by other manufactures. Ford, Rambler, Studebaker, & others used a BW OD so they can be a source for parts.
Fred
