Now lets talk about boat engines since thats what your working on not a car.
Since you have change coils from star to port and still not working EZ stuff 1st.

Check the plug wire for continuity or try another wire if you do not have a tester.
Remove the spark plug and replace it.
Check the wiring to the coil for cracks or breaks or bad connections.

If this do'es not fix it get back to me.

Mike

I take help from online websites that have this service like helping in repair some like reliable-store have instant help.. others are a bit slow which I don't prefer... rest is up to u.. U can also get free manuals