Hello, I picked up a really cheap bayou 220. It starts but won't idle and it has low power. The guy I bought it from just bought it this summer and said it was running fine but would bog down so he cleaned the carb and now it runs like this. The spark plug is black. I decided to look at the timing though, and it's either perfect or off by 180 degrees. When I line up the T on the flywheel with the notch in the threads the indent on the camshaft sprocket is at the bottom. Shouldn't this be at the top lined up with the nick in the case? The timing chain is tight though. Any ideas how this could have slipped?