My brother was hanging upside down, peering through a 9-inch square cutout in a bulkhead at the raw-water pump housing on his 3-cylinder Yanmar marine diesel. “How the heck do you get the impeller out of there?” he asked me.
This is a very good question. Removing an impeller is something that should be done on a regular basis; Yanmar recommends replacing the impeller on this particular model at least every 600 hours. The problem is that its raw-water pump is mounted in such a way that the clearance between it and the starter motor isn’t quite big enough to get an impeller puller onto the impeller. Given the considerable number of years this engine has been in production, in one model or another, and given the large number of units Yanmar has sold, you’d think they would have modified the access to the impeller to make the job easier. But that hasn’t happened. Yanmar, of course, isn’t the only offender when it comes to awkward-to-access water-pump impellers and other items that need regular maintenance.
I called my local Yanmar dealer, thinking he would have some special tools or tricks he could pass along. That didn’t happen. “It isn’t easy, I know” is all he would say. My brother and I worked our way through every tool in our respective toolboxes, fruitlessly trying to find something that would allow us to get a grip on the impeller and pull it out. Nothing worked. Next I went to the local automotive stores, hoping for inspiration. Although I found dozens of different pullers and other oddball tools, I came up empty-handed. My next stop was at the hardware store, and that’s where I hit the jackpot. My prize? A large pair of right-angled needle-nose pliers.