Running too rich-can’t figure it out

Pull the dipstick and smell it. Does it smell like gasoline? Is the oil level higher than it should be? --> --> --> faulty fuel pump leaking gasoline into the crankcase, which gets sucked into the intake tract via the PCV valve—progressively more and more as the engine warms up. This would explain your constellation of symptoms, including the engine staying running with the idle mixture needle seated.

But so would a carburetor too faulty to be fixed with a rebuild.