Roof A/C Fan Motor

Your problem sounds more like a bad start cap than the motor, Less than 20 bucks may fix it...

However That Styrofoam block you mentioned, well there is a way to open it up, what that is I can not tell you since mine is different.. Once you get it open and the fan removed from the other end of the motor shaft and the mounts released the thing lifts out, then you can loosen the set screw and remove the blower.

But unless that fan/blower is hard to turn when you first go up on the roof. I'd sooner believe the start cap than the motor.. IF however it is hard to turn, you called it.

What make and model A/C.. (I mean if it's the right one, and I'm sure it is not, I have a spare).

Usually if the fan will start by hand turning it. All you need to do is change the fan capacitor out for a new one.

Been there done that.

Westend - Crazy thing - It'd free up, and run longer, if I sprayed WD-40 instead of applying Turbine Oil. I know the stuff goes away fast, but it was actually more effective than the right product.

That's because WD-40 is made from petroleum distillates and coconut oil, either of which may have less viscosity and shear than the turbine oil you were using. It may have allowed for less friction in that application but that doesn't mean WD-40 is a good lubricant. It isn't. It also has the nasty attribute of dissolving rubber and some plastics.

I've limited my use of it to wet spark plugs and, with the straw top, makes for convenient cutting oil dispensed when cutting aluminum with a power saw.

Sorry to go off on WD-40 but I was in a situation where WD-40 nearly cost the loss of ten lives and a near environmental disaster.

YouTube was the trick! First one that comes up shows the trick - thanks!

I seem to recall that YouTube has some videos on how to install new motors - worth a look.

We really need the Make and Model of the A/C you are repairing. This happened to me with a Coleman Mach 15. I could get the motor to run, but once it stopped for any reason it wouldn't start again. Dismantled the motor, cleaned the bearing sleeves, polished the shaft, reassembled. It STILL would not re-start after it'd been run. I was oiling it with Turbine Oil, meant for motors in appliances.

Westend - Crazy thing - It'd free up, and run longer, if I sprayed WD-40 instead of applying Turbine Oil. I know the stuff goes away fast, but it was actually more effective than the right product.

OP - IF it's Coleman, you should be able to get the fan off the long end of the shaft. Or, push it all the way to the motor. Then the motor, with a piece of the blower housing attached, and squirrel cage still on it, will come out of the housing. On ours, that housing was foam lined.

If you have a Dometic or other product, I can't help much. I remember that many of their newer models are extensively plastic, foam, space age stuff.

I'd suggest to look for the part online and see if it comes with cage attached. Sometimes, there is a set screw that holds the cage to the shaft.

Also, I'd suggest to use WD-40 only on wet spark plugs. There are products out there that will actually lubricate or prevent rust. WD-40 does neither well.