Questions about My new boat

I bought a boat from a guy and he said the alternator was producing too many volts so when you go to shut the boat off it wont kill it. Key off and still running you have to pull the coil plug to kill it. He says that creating too many volts causes it to have an open circuit after its turned off and will just continue to run. Anyone ever heard of anything like that? Can you fix it or just buy a new alternator? Also it has a 750 holley marine carb on it that needs to be gone through, was just thinking about replacing it, Anything wrong with replacing it with a non-marine carb?



Thanks for reading my questions hopefully I can get some help. Thanks!

Questions about My new boat