Thank you for your Help so far. Since I am not a mechanic, I had an in-law who is come over this morning and listen to it.
I started it up and the knocking stopped after 4-5 seconds. It initially ran rough, but smoothed out after the sound stopped. He said that his opinion was that the problem was a bearing located on the bottom of the piston rod, which connects to the crank shaft. However, to me the rockers and/or stuck valves also makes sense. And the rough running could be due to the carburator/choke combination. Could any of you give me additional help.
