Snapper 21351PD - how to completely remove rear wheel drive disc?

[mechanic mark]

https://bsintek.basco.com/BriggsDocumentDisplay/default.aspx?filename=ahenrJvLlSZk

Adjust valves with engine cold. See page 39 in manual above for engine identification #'s.

 

[Gord Baker]

If it is working, don't fix it. Replace the Spark Plug.

 

[Setec1987]

Thank you both. The spark plug is new as of 3 months ago. I'll look into the valves.
This mower belonged to a landscaper, and I think that it saw heavy use based on all of the dirt that I cleaned off of it.