From your post, it appears that the engine probably hasn't been run for a number of years. So DON'T start it. Any
oil that was left around the moving parts has probably dried leaving everything ready for desaster. Beside changing the
oil, filter and coolant, take out the plugs, squirt some
oil in each cylinder and try to turn over the engine with a wrench on the crank damper nut. Turn it over at least twice. Then pull the dizzy and use a reverse rotation drill motor along with a hex shaft and spin the oil pump to prime the engine. If all goes OK, you can probably try starting it. That's providing the carb isn't gummed up, and, and, and
