- Mar 20, 2007
My boat was hauled on short notice at the end of October for Sandy, so I had to do my winterization on the hard. Somehow in the process of running antifreeze through the raw water side of the Yanmar 3YM20, the flow got interrupted for a few seconds, and then the pump quit working:cry:. When I checked the impeller, it was missing 2 vanes. I replaced it with an old one and finished the winterization without any problems. As I thought about it this winter, I figured I'd better find the broken-off vanes before I recommision this spring, so went searching for them yesterday. Started with the pump outlet - no sign of them. Removed the molded pump-to-heat exchanger hose and reamed it out - nothing. Ended up having to first remove the alternator to get at the HX inlet, finally got it unbolted with much loss of skin on my hands, and there they were, stuck in the HX inlet pipe and nearly completely blocking it. Rodded out the HX passages while it was open and reassembled with new O-rings. Altogether, about 2-1/2 hours of work for a few seconds of dry running. Moral: don't let your raw water pump run dry, and carry a new impeller and set of o-rings or gaskets in case you do!