Mercruiser inboard outboard cranks but won't catch/start

We're having some trouble with our 2000 Bayliner Capri.
It has a 3 litre Mercruiser engine.


It's fussy to start. It will crank over and over and over but not catch. This is very hard on our starter and batteries. After about 10 mins of continuous trying it will finally catch and then it will run perfectly for hours. If it's shut off and sits for 10 minutes it won't start again, we're back to square one.


Additional things we've noticed include
- black smoke from the exhaust on initial start up but disappears once the engine has warmed up
- runs a little rough on initial startup until engine warms up
- the boat runs at 175 degrees
- the oil pressure usually sits around 40 when were cruising along
- the tachometer doesn't work


Not sure if these have anything to do with the starting problem but wanted to mention them just in case.


Any help would be greatly appreciated!


Thanks in advance!

Take off the flame arrestor, and make sure it's clean. Then check out the choke operation, it should be mostly closed when cold, and fully open when warmed up to operating temp.