Compressor Problems

I was hoping someone might have some mechanical knowledge.  I have a Badger airstorm compressor that is "having problems."

I've had the counterweight that connects the motor output shaft to the piston come unscrewed a couple times now.   I can screw it back in, but I can only get it hand tight due to the compressor housing.

I've also noticed that the compressor will sometimes not kick back on when the pressure gets low.  Normally, if I have it set for a 20 psi working pressure, it will build pressure to about  25 psi or so, I'll trigger the airbrush and it will drop to about 20 psi and start running.  I've noticed lately that when I trigger it doesn't always kick on again and will drop to around 5 psi before coming on.  It gets back to pressure really quickly, but it makes painting adventurous to say the least.

I am wondering if perhaps the pressure switch or maybe the gasket above the piston might need replacing.  I'm also wondering if there is something I can put on the motor output shaft (like plumber's tape or pipe dope) that will help the counterweight keep from unscrewing.  Any help or suggestions are appreciated.  Thank you!

Groot