Got a porter cable model cffn250n-2 pancake compressor. Today it would not start up after I used it for about 15 minutes. There was a sound of leaking air. The pressure gauge dropped to about 60 pounds.The motor would start and stop and didn't sound right. Sounded like a humming sound. Then it started and built up pressure to the cut point of 140 psi and is holding pressure. Used it a little more and it kicked in and cut off at 140 psi and is still holding pressure. I hope this makes sense because its hard to explain what happened in writing. I hope you can help me. I don't need it to die and would like to fix it before it happens again. Thanks.

Thats the unit I have.
The motor didn't sound right when it was trying to start and kept turning on and off when the air was leaking.
When it started to work right again the motor sounded fine and built up pressure the same as it always did.
No smells. One more thing. When the air was leaking it sounded like it was coming from under the plastic covering. Just checked. Still holding pressure at 140.