This afternoon, I worked on the propane furnace, as the fan didn't work. The furnace was made by International Oil Burner Company of St. Louis, MO. model # DC1520L, 12V 5.6A. The fan motor is a universal motor that requires periodic oiling of the bearings. I suspect that previous owners over-oiled it, and it gummed-up the brushes, as they would not slide (advance and engage the commutator). After cleaning-up the brushes, the blower worked great! It got too late to try it out, but I will tomorrow. Here are some pics for reference.
New brake booster
2 days ago