Marine mechanics are tough dudes, for the most part. Go visit the marinas that are local to you and check out the mechanic certifications on the wall. Mercruiser offers all kinds of training. Dont know the cost of the cert programs, but i am sure they're not cheap. Furthermore the. Boating market has been in a recession since 1999. I am certain that for every person that is making it inmarine engine repair, there's probably 20 that failed.
you would just have to apply as a entry level mechanic just like any other job. usually you have to find a job as a aprentice. when you get the job apply for apprenticeship. when that's done usually then you go to trade school for marine repair. get licensed.