Baffling, Maddening Impeller Problem

[Panamajames]

I just replaced the water pump on my Kohler 8 kw genset. It was leaking at the pump. I put it on and got no water flow. Felt the plate and of course it was getting hot and thats when I shut it down. Burned up a impeller like you did a few years ago leaving the seacock shut. I ALWAYS look for water expelling with exhaust and I always feel the plate on sea water pump now. Anyway new pump installed no water flow. I check for water to the strainer. Water coming in and so I was baffled. I took off the hose and primed it by pouring water down the hose and then reattaching. I then turned it on and ran to outside of boat noticing water spitting a little outside the boat. I then turned it off. I turned it back on and more water spitting. I felt the face plate on the sea water pump and it was cool. I did not like the amount of water flow but as I waited it increased a little at a time. I judge the temperature by feeling the plate. If hot turn it off immedately, if warm I wait and let is cool. When genset is turned off then the plate is quite warm as genset is warm... Hope this helps.

Question where is the easiest place on your Kohler to drain the anti-freeze. Mine is in very very tight quarters and very hard to do anything with it. Changing the water pump was a job. I also had a bad belt that I changed and left off the shroud so I could examine the belt and tension more effectively.

[Panamajames]

I always thought the impeller would find the right direction as it turns. I have been told that and it seems to work for me when I install a new one on the engine or genset. Everyone talks about the spines being set in the correction direction. In mine the find their own way. Maybe I am just lucky.

[Dockhead]

Originally Posted by Panamajames

I just replaced the water pump on my Kohler 8 kw genset. It was leaking at the pump. I put it on and got no water flow. Felt the plate and of course it was getting hot and thats when I shut it down. Burned up a impeller like you did a few years ago leaving the seacock shut. I ALWAYS look for water expelling with exhaust and I always feel the plate on sea water pump now. Anyway new pump installed no water flow. I check for water to the strainer. Water coming in and so I was baffled. I took off the hose and primed it by pouring water down the hose and then reattaching. I then turned it on and ran to outside of boat noticing water spitting a little outside the boat. I then turned it off. I turned it back on and more water spitting. I felt the face plate on the sea water pump and it was cool. I did not like the amount of water flow but as I waited it increased a little at a time. I judge the temperature by feeling the plate. If hot turn it off immedately, if warm I wait and let is cool. When genset is turned off then the plate is quite warm as genset is warm... Hope this helps.

Question where is the easiest place on your Kohler to drain the anti-freeze. Mine is in very very tight quarters and very hard to do anything with it. Changing the water pump was a job. I also had a bad belt that I changed and left off the shroud so I could examine the belt and tension more effectively.

Your last question first -- I drain the fresh water cooling system by popping off the hose flange next to the drain plug, on the exhaust manifold. The drain plug on mine seems to be frozen but the hose flange is at the same level so seems to work ok.

Thanks for the other comments. All this about hot sea water pumps is new to me -- never experienced anything like it before.

A question -- can it occur as a result of overtightened cover plate?

[Stu Jackson]

Using petcocks on engines of any kind to drain them is usually asking for trouble, because small debris can get stuck up in the petcock and jam it in an open position. Not good. I agree, and always use hoses to drain my coolant.

Usually too loose a pump coverplate is the culprit, or the gasket is the wrong thickness, or the faceplate is scored inside and needs to either be replaced or sanded down flat.