Small Engines (Lawn Mowers, etc.): correct sparkplug gap, sparkplug gap, silver series


Question
Hi,I have a Lawnboy Model#7266 the 1977 version and was wandering how to determine the correct sparkplug and gap for that mower?

Answer
I tried looking it up using 3 different sources, But seems there can be 6 different engines used on that model. I would need the information on the engine. 2 stroke or 4 cycle (do you mix gas and oil or not)...Manufacturer of the engine...Gold pro series, silver series? I could take a guess but would rather not. The wrong plug can damage your engine....Tom....