Welcome to the forum.....
Joe, that's a good question!...You don't state what model your 1998 ski is, there were two different model engines made that year. But if I'm thinking about what your thinking about (offset a little to the side at the exhaust manifold), that little piece of metal is your grounding lug and is used to put your spark plug wires on while not in use or while testing. The electrical surge from your coils should be discharged through those lugs if your working on the system. If you don't, you could damage your electrical system. But if its gone, just make sure you lay the plugs across the engine, they'll find a ground when you roll it over..........
That's it?.........boy, that was the easiest question I had in a long time!
Thanks for asking and please remember, there is no question to small if you need an answer. Nothing !:cheers: