I have a 575 SCI single engine that started running extremely rich to the point that I couldn't get my boat on plane with a plum of black smoke behind the boat. Any suggestions sensor related ?

bad map sensor would be my first guess

thanx for your response do you have or have had this engine with same problem.

I would say to do some basic checks, fuel pressure, code scan, and check MAP data?

i know the injectors can be a issue as well

Yes - odd ball injectors - no longer available. Check with BUP or Dave at MDG performance in Md. Eddie Young makes an injector kit to replace the obsolete TBIs.

i have eddies kit, super nice. also have stock injectors with low hours if that ends up being your issue