On a previous
boat I had a Yanmar
3GM30 for which I needed a replacement
raw water pump. In
Australia I was quoted in excess of $800 for it. When I reproached the dealer for the excessive cost he said that whilst the pump might look like a standard Johnston pump and use many of the same
parts it was manufactured specifically for Yanmar engines hence the high cost.
I went and bought the same pump with a standard mounting foot from a
chandlery, made a mounting plate from a piece of alloy angle and got out of the
repair for about $240. And, since the Yanmar plate was
steel and I'd have to take the pump off, clean of the rust and repaint it I no longer had to do it with the alloy.