Furnace Blower Motor question

Pull the motor / blower apart and simply spin it with your fingers. feel how "free" the shaft is. These are generally bushed, and not ball bearings. Note now it was mounted, IE vertical orientation. Punch small holes in the end caps "up" and use a "zoom" oiler or other device to inject 20WT or similar oil into the bushings. If they seem "free" that part is OK. Blow any dist / lint out of it if necessary pull the motor apart to inspect internally.

Don't be afraid to wash out the blower and housing. Use a hose, detergent. That is what your dirty jeans are for

If the motor does turn free, there's only two things left............voltage, that is, the switch / relay contacts, and the cap

You can easily check the switch contacts. Be careful, as these are usually multi speed with only two hooked up. That is, example, the "red" hooked up for low speed on heating, and the "black" hooked up for high speed on high speed on A/C or "summer" fan There may be a couple of "in between" speeds, yellow, blue, unhooked, taped off

So get the thing in a position where you can run the blower. You MUST run the blower with the compartment CLOSED OFF. The blower draws too much current with the blower compartment OPEN. You must run it in a "normal" configuration. So look beforehand and "rig" a meter in such a way that you can measure voltage to the blower terminals to determine if the switch is delivering full voltage. Additionally if you have a clamp on ammeter, you can check load current

If the thing is getting full line voltage and won't start correctly, I'd try a new cap.

As you guys know, I'm NOT a guy who advocates "throwing" parts at a problem, but if you really suspect this, and the bearings are free, this would be one of those times. Caps are cheap. Make certain you get one the correct rating. You want the correct "microfarad" and AT LEAST the same or more AC voltage. It can be for more voltage but not less.

You do NOT want very much deviation, either more or less, on the microfarad rating

Don't however, expect these motors to rip up to speed. These are a low torque device, especially on the "low" heating speed, and normally take several seconds to do so. Stop and think if it's 'acting normally' or if things have changed. Have you noticed any smell, IE is the motor running hot?

ALL of this used to be part of my normal service routine. Some of my customers were amazed. "None of these other guys ever............." I guess they must 'ove just stood there and LOOKED at it then LOL