My friend has a boat of 1984 Bayliner Cierra 2755 260 volvo penta. It Runs and drives but once it reaches operating temperature shuts down. What issue is there? Is it easy to fix?
check the condition of the raw water impeller
check the distributor, cap, rotor, plugs and wires
check the fuel system - specifically fuel quality, choke settings, and condition of carburetor
check engine compression
I have heard form a local mechanic here in SW FL that the ignition coil causes this problem if it's a recently installed after market one. There is a MerCruise replacement that he has the part number for. I can get it if you can't find it. He has had a recent bunch of calls (mobile mechanic) for this exact complaint/issue.