It's supposed to be mounted to the engine! That's why it comes with bracket and bolts. Check the wires going to the coil as they are in a different position when mounted. You could unmount the coil, start engine, move coil around to see if engine stalls. Another test: with coil unmounted, start engine and ground the mounting bracket of the coil to see if engine stalls, if it does, coil is defective!
Note: these coils usually are NOT the cause of no spark! Keep this in mind if this coil thing don't pan out!!! Post results for more info..