I was wondering how long an Excavator engine can sit before valve seals or any other problems could come up? I haven't worked it for about a year and probably won't till next spring. I've started it up every couple of months but no heavy work.
As far as valve seals and other plastic/rubber parts go, it depends on the manufacturer. I have seen large natural gas engines stored for more than a decade without problems. Nucle oil was used to displace oxygen.