Small engine questions?

Hey I'm trying to fix my gokart engine and learn about how the engine works while I do it, since I'm basically teaching myself. Here is a short video I made of the engine(http://www.youtube.com/user/panic3597?feature=mhee#p/a/u/0/fSSJTE-e0yA) . I believe the engine is seized or for some reason the flywheel is stuck. I've taken off the engine covers and the exhaust, and uscrewed all screws relating to what I think is the top of the cylinder head that is supposed to be able to be removed. 1. My first question is what is that little black box with the hoses coming out of it that's showing at 0:24 in the video? 2. What part of the cylinder head comes off so I can see the piston?!!? I cannot seem to figure it out anywhere, I thought it was the very top maybe an inch into it?? 3. Any suggestions on how to get this thing unlocked??