If the engine is more than a few years old, it may have valve
clearance problems. To check this isn't all that hard, with a
socket set and a couple of feeler gages.

To fix it requires dissembling the engine, and not many people
have the tools. I tried to make a living of small engine repairs,
and I do have the tools.

--

Christopher A. Young
You can't shout down a troll.
You have to starve them.
..

wrote in message
ups.com...
: I have an MTD, self propelled lawm mower with a 5.5 HP Briggs
and
: Stratton engine. Over the last several weeks, it has developed
a
: problem where it starts right up, runs for about 20 minutes and
: stops. Sometimes it coughs and sputters for awhile before
stalling,
: other times it's as if it was turned off. There have been
times it's
: done that and would restart, other times, I have to wait until
the
: next day.
: I have checked the air filter, checked the gas line, and
checked the
: spark plug cable. What I haven't done is replaced the spark
plug.
: If this helps, I thought it started moving alot faster about
the time
: it happened but for the life of me, I can't see how that would
be
: connected to the problem.
: