I thought I would run the engine yesterday for the first time in a couple of months, a few minutes later the overheating alarm went off.
There was water at the outlet from the water strainer, so I took the pump off then it's back. When the shaft was turned the impeller didn’t, the bonding between the rubber impeller and the metal centre had failed and it was easy to separate the two.
The water pump looking from aft. |
Visually in good condition except its now in two pieces. |
On a Yanmar check and if necessary replace the water pump belt regularly, the unit gets very close to the engine mount if worn and adjusted for the correct tension, this could be a particular problem if standard soft engine mounts are used as the engine will rock more. Fortunately I have the stiffer premium mounts.
Update 4 Jan 2024. With a brief break in the weather the engine got it's annual service yesterday along with a new drive belt for the water pump and new water hoses from the pump through to the anti-syphon valve and the exhaust elbow (the seacock to the water pump were replaced with the seacock in 2022), rerouted to hopefully avoid chafe. Everything working again.