Exmark 48 belt drive

[Juandingo]

Machine stalls occasionally when blades are engaged. If I flip the little lock on the left-hand control it smooths out. Just recently it stalled completely. Started up and ran fine the rest of the day. It's done it enough in the last few weeks that I work that left handle with thinking about it. Any ideas? Runs great otherwise. Thanks

 

[mechanic mark]

For Safety remove negative cable from battery. Check air gap at three windows on PTO clutch.