It's been a while ,so I kinda forgot about what I did back then. It has worked great for the last couple of years, and I believe all that I did was to turn the cover over, as the scoring was causing it to be less powerful than needed, to overcome the siphoning. I did also replace my cheap
plastic raw water
strainer with a good perko one, but can't remember if this was before of after.
If you have scoring on the cover, and the other side is flat / same shape, it is worth a try. The old 1982 Yanmar
is still going strong, although I only motor
around 50 - 80 hours per year.