Hi,
There is considerable vibration from my 1.9L waterboxer.  It will run
fine and idle fine.  Power is good.  However, it does this strange
shaking hula dance in my engine bay.  Not too bad, but it's shaking.

I bought the engine used.  The engine was sitting idle for a while (not
sure how long) in a parts van.  I've changed the oil once and adjusted
the valves a few times.  I'm going to adjust the valves again this
weekend.  I'm trying to think of other ways to trace the vibration
problem.  I've run Marvel Mystery oil through the system and I've used
fuel injection cleaners twice.  I've recently changed the fuel filter.

Things I'm thinking of replacing:
  - distributor rotor and cap
  - plug wires
  - plugs

I'm not sure if this would make a difference.  I think I bent one of the
wires that connects to the distributor cap, but I still think it makes
good contact.

There was a tapping sound before, but since I adjusted the valves the
last time, the tapping sound went away, mostly.  However, the unusually
strong vibration persists.

What should I look at?

Thanks.

Regards,
Craig