Weird startup

[Matt]

When i turn the key all i get is a grating/whirring noise (similar to turning key with engine running), then after a random amount of time (average 20 secs) a "clunk", the feel of something unsticking and engaging, and starts as it should.
Starter motor "something-or-other" sticking inside maybe?
Anyone know what it may be?
Cheers
Matt

[geeves]

I would be looking at the starter motor first It sounds like the solenoid isnt pushing the pinion into the ring gear probably due to mud or rust A clean should fix