3 hp Tecumseh misfire

[0352]

I have a 3hp Tecumseh engine on a mini bike that has a intermedant misfire while idling. Is this normal for these engines? Should I run a higher octane? Currently I'm running 87 octane.

 

[0352]

I cleaned the spark plug and that seemed to help a little bit. Is this a indication that the ignition coil or points and condenser are going bad?