On Friday, June 5, 2015 at 8:02:28 PM UTC-4, Mr. E wrote:
On Fri, 05 Jun 2015 18:07:58 -0400, Arnie Goetchius
wrote:

I have a tractor (MTD 1998) with a 14.5 OHV Briggs & Stratton. The
starter has been giving me fits over the last year or so. The starter
would not turn the engine over. I tried to turn the engine by hand but
could not.

Have brand new battery and some times I can jump start with the car
battery and will turn over. Once I get it running, there is no problem.
If I turn it off for an hour, it will start right up. Leave it off for a
couple of days and the starter will not crank. Any ideas?

A lot of these engines use the exhaust valve in a compression release
scheme to allow the starter to turn the engine over. The exhaust valve
clearance must be set at the prescribed point in the rotation of the
camshaft to allow this function. Check the manual and verify if the
exhaust valve is gapped correctly.
--
Mr.E

+1

A neighbor was having the same problem with his lawn tractor.
We had it misdiagnosed as a bad starter. Even with a fully
charged battery jumped to the starter, it would engage, but
not turn over. He wound up calling for service and it was
that it needed a valve adjustment. Which didn't seem to make
sense at first, until I thought about the compression release
part.....