I recently bought a used 2086 with Kawasaki liquid cooled engine. I was wowing with it today. Everything was fine for 45 minutes or so. Then it lost a bit of power and shut down. Turning the key all I got was a click. I let it cool down and then it started but it did not have much power with the mower on so I returned it to the garage. Any idea what may be causing this? Thanks!