Matt - Measure the resistance of the coil - this will tell you if the coil is defective. I think not - but it is worth a shot.

The assembly itself could be out of adjustment ? If the plunger is too short - it travels further, thus becoming more powerful. When you shopped the game - did you replace the plunger with a shorter one perhaps ?

Nah, didn't replace the plunger (it's actually a cup) all original.