Will anyone give advice on how to do a compression check on a motor that you are wishing to purchase? I bought a nice, used compression guage, but have never used one. It came with no instructions.

How many times should I crank the motor?
Just a couple of taps?
Does the correct lbs. have to be applied? or can I just thread it snuggly? (sounds bad)

Any and all advice would be appreciated.

Thanks!

oz