Re: Help with 1979 Watkins 27 diesel ID
Make sure you think this through and as part of your thinking you should seriously consider Maine's advice to find another boat.
You need to remember that you don't install an engine---you install a propulsion system. The propulsion system includes a fuel system/cooling system/exhaust system/instrumentation system/controls system/electrical system and shaft system including the prop. Are the components of all these systems in place and in working order? Fuel tank and fuel filters? water filters? control cables? starting battery? exhaust piping and muffler? shaft log and bearing? propeller? instrument panel? Associated valves/piping/wiring?
Making these systems operational and reliable by restoration or re-installation is a major expense. I just completed a complete restoration of a 27 footer whose engine and associated systems were all beyond salvage except for the shaft and prop. Even with a "free" engine that I had sitting in my shop and doing all the work myself the installation cost about four grand.