I have a 2002 Simplicity Broadmoor 1600 series with a 16hp Intek Twin V Briggs & Stratton Model 405777 Type 0134-EL with less than 225 hours. Serviced

My problem: We mowed yesterday and when completed turned the mower off. About an hour later came back to put the mower away and it would not start. I can hear the solenoid click but the starter will not engage. The battery is less than a year old and fully charged. I pulled the starter and took it to Auto Zone who tested the starter. I watched the starter engaged with no problem. Auto Zone claimed my problem is not the starter.

I'm at a loss any ideas?

Thanks Ed