Re: Overheated my Yanmar 20gm20f
Seems to me that would work with a small hose clamp on it. Yanmar, I believe, recommends that the valves be adjusted after an overheat. Like others have said check the oil which, you might want to change for the heck of it and look to see if you're putting out a lot of smoke when you start her up. If not you're probably fine.
I overheated my 3gm a few years back and it was obvious that I had damaged it (burned up a piston ring). I had excessive smoke when I started the engine until it warmed up. My mechanic said run her till it dies. I lasted one year before I got tired/embarrassed about the smoke on startup.