Well I would start by removing the belt and starting it up for a minute to see if it goes away. If not, I would start pulling spark plug wires carefully with a pair of pliers and a gloved hand one at a time to see if the sound changes, or stops on any of the cylinders. But that's my best guess over the interweb. Good luck.
When you pull a plug wire to check put it back obviously before you go to the next. Do not pull your coil wire while it's running. I learned that the hard way.
Originally Posted by jabba974
"And yes, there is always a torque spec...but its not necessary...and takes way to much time...."