Fresh Water Pump

[Moody46CC]

I have a Yanmar 4JH2-TE engine in my sailboat. I had moved the boat from the dock to the travel lift and back in December. When checking the boat in January, I noticed some engine coolant pooled on the bilge pan under the engine--directly under the forward edge of the engine. Is that likely coming from a leaky or shot fresh water pump? Can the water pump and connections be tightened or should it be replaced? 1210 hours on the engine.

I don't think it is raw water anti-freeze because the water pump">raw water pump is off to the side and separated from the engine by a stringer which would block any discharge from the raw water pump from draining under the engine.

[sailormed]

Most probably a leak in the engine waterpump seal on the pump shaft. There is a hole under the pump shaft in front of the engine made on purpose to leak the water there so it is an easy diagnosis. My Yanmar 3JH4E has a belt cover that you need to take off to inspect that area. My engine had 1100 hours when it started leaking there. A bit early and somewhat expensive.

[a64pilot]

I’d verify the pump is leaking before I pulled it though.
There is usually a weep hole that the liquid will leak from, this hole exists I believe to prevent the leak from leaking into the engine oil.
You can buy or borrow a radiator test kit, small pump with a radiator cap and pressurize the system and just wait, usually before long you will see the leak.

[Lepke]

Most engine coolant circulation pumps can be rebuilt. I rebuild mine. Usually the pulley needs to be pressed off and sometimes the impeller, too. After that is a simple bearing and seal replacement. A good bearing supply that carries US and metric should be able to match the parts. Even if you pay full list price on the bearings and seal it's less that 20% of the price of a new pump.