Sherman wrote:
My 4 year old lawnmower gets hot and dies. I can mow for 15 minutes
and it coughs and sputters and then shuts down completely and will not
restart - for 15 minutes. Then it will start and runs another 10
minutes.

Seems to be a heat related issue. I cleaned out the debris and
replaced the spark plug. No change.

What could be wrong and how do I determine it?

Sherman

Many, many air-cooled engines develop this problem. The odds are
overwhelming it's your ignition module, and they're a ******* to
troubleshoot [except, of course, by replacing the module].

As soon as the engine starts to cool -- long enough to check for spark
-- the module cools down enough to check as OK. It's very possible
you'll check the spark and it'll be OK.

They're easy to change, but shop carefully. The price for replacement
can vary radically.