Ok, so I had to change the head gasket on my KA24DE. Prior to doing that the only mechanical work I've ever done was changing the oil on the 4 wheeler. So now after a week, I've put the head back on, everything is back on and it won't start. I know I have sparks because I pulled out the wires and saw them. I also think I have fuel because I can smell it. I am completely stuck. Has this happened to anyone before?