Buzzing outboard starter..

Hi
I have a 45hp chrysler outboard electric start. Occasionally when i try to start it up the starter does no move, simply making a humming/buzzing noise. The starter will turn freely, then will continue to hum/buzz when i try to start it again. This only happens sometimes but is getting annoying. No sure what the problem is, but then without doing anything it will start up fine..
Any idea??
All help is much appreciated

Cheers, Aidan

Ayuh,... Pull it off, take it apart, 'n Clean it...
The brushes might be gettin' Bad...

Not ever worked on a Chrysler OB. But before tearing down the starter, check the wiring and the solenoid. Often times, "starter failure" is just a bad or weak wire connection or a bad solenoid. So remove each wire from the starter and starter solenoid, clean it thoroughly, and reconnect. Next, make sure your battery terminals are very clean and make good contact.

The solenoid mechanism is typically attached to the starter itself with a heavy gauge wire coming in from the battery and the other going to the starter motor. There will also be one or two smaller, light gauge wires attached to that solenoid. When you turn on the key to start, that completes the circuit and energizes the solenoid relay through the small gauge wire, which in turn completes the circuit of the heavy gauge wire and energizes the starter. Simply run a wire from your boat's positive battery terminal (or any other positive side terminal) and touch it to the small gauge positive wire attached to the solenoid and listen for a loud click from the solenoid each time you energize it. If no loud click, or it is the source of the buzzing, then replace the solenoid.

If the wire cleaning and the solenoid test doen't fix the problem, remove the starter and take it to a test & repair shop. They are typically very easy to rebuild.