Over the years I've noticed when I turn the key on I'll hear a pump running from time to time. Doesn't happen every time I turn the key, probably close to half the time. I've never delved into the workings of the motor since it has been so reliable, I just change the lower unit oil and impeller once a year.
I did have to change the upper oil reservoir when the magnet fell off the float 3 years ago, but that was 35 bucks and 30 minutes of my time, so that was easy. Other than that, not one issue.