I have a Steel King 4800, mine has a Fasco blower. They are cheap, bushed motors. Mine has come to a stop a few times. Clean it up and a dab of oil and they take right off again......... usually. You will more than likely have to remove the blower and drip oil into the bushing from some opening. There are no lube holes on mine at least, so that is how I do it. It has stalled maybe twice in 14 years. Make sure you get the cups of the squirrel cage blades real clean. They fill up with dust and debris and reduce the volume of air delivered sharply.
I would like to see some pics of this twin blower deal.
Do you know where to get coal grates for these guys?