Small Engines (Lawn Mowers, etc.): Lawnmower engine dies & not restart, model numbers, fish

Question
Hi John,
With your help in the past I was able to isolate my lawnmower problem and determined that it was a carburetor problem so I replaced the entire carburetor with a new one. It was running good for a while and now the problem is that the engine would die after mybe 5-10 minutes and I cannot re-start it. But it usually starts after sitting for a while like overnight and would die again as before. What could the problem be? Can you please give me some tips? Thanks!

Answer
I don't remember the discussion before, so I don't know which engine you have.  Offhand, I would say that the valves should be checked,
their clearances sound too tight.  If you could let me know the engine's model numbers, I could tell the way to check the valves.

Thanks,

  Fish