Ok, I'm feeling really foolish. Today I noticed something for the first time -- and we've had our '07 150 Speedster for 6 years and 190 hours of operation.
When I first put the DESS key on the post, the Information display area shows the following:
MAINT (flashes a couple times)
then reverts to the normal NORTH (or whatever direction)
Has it been doing this all along and I've just not noticed it? Or is there some maintenance I need to do? I do most maintenance myself -- oil changes, winterizing, etc.