Running and starting problem(s)

I have a Craftsman Mower with a B &S engine Model: 31070 0136-E1 001018ZD. I have recently started to have, what seems to be 2 problems. After running for about an hour and a half the motor cuts out. It seems to be under strain and stops. It cannot be restarted because the starter motor will not turn, though it takes power as shown by the ammeter.

Left to cool over night it has re-started OK. However today, the starter turned the engine but it would not start. I removed and cleaned the plug, checked gap and tested for spark. All fine. Replaced plug, turned over engine and nothing. I removed plug and wanted to test for a spark but the starter motor would not turn as above. The engine can be turned over by hand by directly turning the screen on top of the flywheel. I plan to take the blower housing off tomorrow and look for any grass build up and loose wires. Any other help/advice appreciated. I have looked at the Briggs and Stratton site. I'm just not sure if I have one or multiple problems.



Thanks