Got my generator mostly torn apart, except for the field coils in the yoke. Wow are they tight. Book says don't remove them unless necessary, so that's fine, I won't. Generator tested good, but it needs cleaning badly, which is why I disassembled it.

Question: Can I submerse the yoke/field coils in solvent (mineral spirits) to clean it without any damage? Just want to clean it and get it back together. Thanks!

Stator and armature coils can be cleaned using solvents followed by hot soap and water. Both will require baking at about 280 Deg. F for 6 hours. After baking a megger test needs to be conducted to ensure nothing is grounded and the coils completely dry. The coils of both the stator and armature will require coating with air dry electrical varnish. Check the commutator segments for high mica and undercut if necessary. Do not get varnish on the commutator. Check the brushes for wear and the brush rigging for freedom of brush movement. Unless you have experience and the required test equipment or know someone who does I would not recommend doing this. An alternative would be to spray the parts with brake/electrical cleaner and clean with a soft brush. However, you run the risk of damaging the insulation and/or forcing contaminants into the windings.

Yeah, sounds like I might be in a bit over my head with that process. I guess a gentle cleaning (solvent/liquid free) will have to suffice. All parts look good; brushes, holders, springs, wire connections, etc. Just dirty. Thanks for the advice, I'm taking it.

I think I would wash them in diesel and then drain and let them dry. Mineral spirits shouldn't hurt them, but the steel will tend to rust quickly afterward.

Its not rocket science and you could do all the tests described above. However, many a shadetree mechanic has cleaned up a generator and reassembled it with good results.

Don't forget to cross the field leads when you reassemble.

Thanks, Ted. Got it cleaned-up this evening and will paint and reassemble. No solvent/liquid on the yoke or armature, just cleaned off as much grime as possible on the field coils. Wire-wheeled the casing, and cleaned the brush assembly with mineral spirits and dried thoroughly. Hopefully it will run as well as before I took it apart!