DO NOT TURN THE CRANK SHAFT.

Remove the carb. Some say to look inside the case to see if any dirt got in, and if it looks clean just clean out the carb. Personally I like to open the engine and check and clean everything.

The carb is easy to open up and clean, fairly self explanatory.

There is a great video for opening up your engine, [link=http://www.youtube.com/watch?v=TuzEco3EDUM]here.[/link] It is a 2 part video.

You can clean your engine with alcohol, extra/dirty fuel, or you can use water if you are sure to rinse it thoroughly afterward with alcohol. The video shows how and where to lube when reassembling, and talks about the different lubricants available. I use marvel mystery oil.

People say that once you open an engine, you are never able to get things back together EXACTLY as they were before, meaning the piston and sleeve will not be exactly aligned. Every engine I've crashed, opened and cleaned, runs as good if not better than before.