It's not a big block...

[83hurstguy]

Nice mower! We have a 50" entry level Timecutter with the Toro 24.5 hp engine and it's been great, other than the deck idler pulley bearings going bad about every 100 hours. The pulleys are sheetmetal and assembled with the bearing inside, and you can't replace just the bearing with something of quality. It's the stamped deck (not welded like you have), and you can't hear the pulley bearings go bad over the mower, you feel it with the belt off when hand spinning.

Be careful with that deck washing system, the decks like to collect clippings in some spots, and adding more water just leads to faster corrosion. My father in law was a Toro dealer for 50 years until he recently retired and told us not to use it. Seems like it's either a "use it every mow and keep it spotless" or just forget about it and scrape it periodically - we just pull the deck once a year for maintenance.