If you need to change the recycle settings on a WSUS server running server core, it can be done via Powershell :
Import-Module WebAdministration Set-ItemProperty -Path IIS:\AppPools\WsusPool -Name recycling.periodicrestart.privateMemory -Value 4194304 Set-ItemProperty -Path IIS:\AppPools\WsusPool -Name ProcessModel.shutdownTimeLimit -Value 00:05:00 Set-ItemProperty -Path IIS:\AppPools\WsusPool -Name ProcessModel.idleTimeout -Value 00:00:00