Re: 6 hp fisherman running hot
Welcome to iboats.
I'd answer your question, but then all you'd learn is the answer to one question. I'd much rather send you to johnson.com and tell you to navigate through their website to Parts & Accessories where you'll find Engine Diagrams in the Literature section. Your answer lies there, and yes it's a 1968.
As a side note, overheating is rarely caused by a thermostat.