Ingersoll Rand compressor model 2475 motor stalls

When turning compressor flywheel with belt off it has a hard spot that you can still turn past by hand but motor will not. If i pull the oil fill plug on the crankcase I can hear air hissing slightly into crankcase. Once compressor running its not making any knocking noises or anything like that.

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Bill says...

Sounds like it could be damage to the crank, or piston / seal or uneven wear.

If the motor won't push the piston or rotate the crank past the spot, then it must be pretty severe.

As far as I'm concerned, if it were my compressor, it's tear down time.

Cheers,

Bill