Best outboard for Windrose 18 sailboat

Just bought a decent Windrose 18 which is ready to sail except for no outboard. Thinking about a 5 or 6hp older 2 stroke to get me started. I do have access to a nice older 8 horse Johnson (early 80's?). Is that too much power? Can it be run at reduced throttle to compensate? Were those motors particularly bad or good? Can newer oils be run leaner for less smoke? Any particular spare parts (other than plugs) that should be carried in the boat? Ya, you're right-it's been a long time since I've been boating.
Thanks,
Don

 

Two horsepower is about right for your boat. Sailboats don't like too much weight hanging out their ends. A four stroke is nicer--- the fumes aren't as bad when going downwind and they are practically silent.
More HP won't increase speed hardly at all. You're limited to about five knots regardless of motor size.

 

I like engines with reverse, so this limits my choices to 4 HP and up, but Alan is right, you will reach hull speed with a 2 HP engine. If you need to punch through chop and contrary currents, a 3 or 4 HP is more than enough. An 8 HP would be dangerous.