Could a tight choke cable cause this? I just happen to think of it as I walked out the door this morning. I checked and there is no play in my choke cable. I'll re-adjust it after work today and see what happens.
I had a snowmobile that used to do the same thing, now the engine is being rebuilt. I had a bearing go out, piston crack, cylinder head got all scuffed up from metal particles inside cylinder, the rod that pushed that one piston got tore up, and I have to by a new bottom end for it. At first I thought the bogging was due to clutch and/or plug issues but it turned out to be a lot more serious. Was caused by one screw in the bottom end coming loose and started leaking oil and burned the engine up. So you gotta be pretty careful about these kind of things.