Thanks for your reply. I pulled the air cleaner and intake hose. I found a ball wad of plastic (similar to electrical tape) in below the air filter. I ran it again and had slightly better rpms. As you said in your post, it didn't stop right at 3500. It accelerated slowly past 3500 up to 4000 rpms. At 20 mph in neutral, I could run it to 6000 rpms a couple of times. At 40 mph it would only go to 3500 - 4000. It does sound like its starving for air. I think I hear a slight miss or pop occasionally, but I think the timing is okay. And it idles fine. Also, the exhaust looks straight, although the muffler does look like its rusting and needs to be replaced.Thanks.