Learn a lesson on bad gas

I had bad gas in my john deere lawn mower, 20hp ohv, it ran fine then the next time would not start. I pulled the valve covers and both intake pushrods had fallen off.
I put them back on and noticed that when I turned it over the intake valves were slow to close at first and then they got better. After new gas and seafoam they ran fine.

Same thing happened on my slant six.

Just because something didn't happen to you doesn't mean it can't happen. I guess it all depends on the tolerances of the valve guides and the strength of the valve springs.