Re: 1997 force 50 hp poppet valve
You didn't say exactly what your overheating problem was but it is a sure bet that a partially open thermostat is adding to the problem. Unlike autos, a broken head gasket usually will not contribute to overheating.
As I said before, replace the thermostat and impeller. No matter what the previous owner said, do it. Impellers can be destroyed in as little as 30 seconds. The 20 bucks it costs for a new one will be worth the peace of mind and it is not a difficult job to do yourself.
You can also run without the thermostat until you can find a new one to install.