Hey Splash. Sorry to bump an old thread but I've got the same problem with my 2006 ETEC 90 that's started in the last few months.
At first it would take 2-3 turns of the key to get the engine to crank, now it's 5-10!
Upon closer inspection I noticed that when engine fails to start, the bendix just spins relatively slowly. But when it does crank it spins up very fast and starts immediately.
We've given it a small clean of excess grease around the collar, so my next step will be to check battery and starter motor terminals and leads.
I was interested to know what fixed yours in the end.
I've got it booked in to Downes marine in 2 weeks in case we can't fix it. It's just not worth the risk of getting stuck out somewhere with a dead starter motor.
Matt