So I've got a searay 2009 175 sports with a mercruiser 3.0. I get it serviced 2 x per year. Had service 6 weeks ago so it's summer here in Austrslia. I've been in the boat almost daily but it has been labouring can't to start and then last time (2 days ago) the smell of fuel was stronger than normal. So I go to start the boat this morning and turns over but won’t start. I have 2 batteries but put a jumper on it and no start. It’s got petrol, charge not sure what’s wrong? Any ideas?