markd wrote:
I have a 9 year old MTD lawn tractor w/14.5 Briggs & Stratton. It
starting having issues turning over at the end of last season and I
attributed it to a battery going south. Once it'd start it ran great
however. Now this year it'd turn over *real* slow once, maybe twice
and that's it. Replaced the battery since it's a few years old, but
same result.

I pulled the spark plug and it turns over easily. Put the plug back
in...problem returns. Could this is be an indicator of a valve
problem (since problem occurs with compression) or just a 'weak'
starter?

Any help is appreciated.

In my experience starters don't get get weak, they either work or they
don't. I would check for bad connections at the ground cable, solenoid,
and starter. If any of these connections get hot when trying to start,
you should clean it thoroughly. Also check the battery you bought to be
sure it is at least 220-230 cold cranking amps (cca), 260 would be
better. A lot of the $19 walmart batteries are 140-160 cca and just
don't have enough juice.

Valve problems would cause less compression, not more.

A build up of carbon can cause increased compression. Usually this is
only a problem on poorly maintained machines. Constant running with a
dirty or partially clogged air filter will cause carbon build up over a
period of time. Cleaning it is as simple as removing the cylinder head
scraping the carbon and putting it back on. Always use a new head gasket
and torque the bolts to 12-14 ft-lbs. Removing excessive carbon build up
will make it easier to start and increase the power output.


--
Art