I have a 1991 Bayliner Capri with a 3.0 mercruiser. So here is my issue the boat has had this problem for years it will start and idle for 2 mins or so and die but if I put it in gear it’s fine I can drive all day wot with no problems but if I brink it back to idle it will die. And the only way I can get it to start again is if I push the throttle all the way down and let it turn over for about 15 seconds once it starts I have to let it rev up then I just have to keep feathering the throttle until I’m ready to get back in gear and go. And when it does start back up it smells really rich.