How to test if water pump is working properly

NOLA26

Cadet
Joined
Feb 26, 2019
Messages
18
I have a 2001 Mercury 10 HP Saltwater Series outboard motor that is new to me. I was told by the previous owner that the boat/ motor haven't been in the water in about three years. The motor appears to be in very good shape. After changing the water separator filter, fuel filter, and primer bulb, I was able to start the motor and it ran really well. I went ahead and replaced the whole water pump just to be on the safe side. After the change, the stream from the pee valve was just about the same and the temp of the water was only slightly less hot that the original pump. Is there a way I can test to see if the proper amount of water is being sent to the engine at the proper pressure? I did notice that the tube going from the water pump to the motor is a copper pipe. I thought it odd to have a copper pipe there but it was in good shape so I reinstalled it. Not really sure how it is secured into the engine but it felt like there was some kind of grommet and I felt it seat into the port when I reinstalled it. Just making sure this is the proper part and that I reinstalled it the right way. Thanks for any help or advice.
 

The Force power

Commander
Joined
Feb 3, 2019
Messages
2,359
The copper-tube is correct & it will have a rubber-grommet inside at the top and bottom. If you followed the instruction on how-to replace the Impeller(the fins are facing the right direction) it should be pumping as it should I'm not quit sure what motor you have but most Mercs. are the same. If your motor is equipped with a thermostat; it maybe stuck open. Also the majority of return water is going through the exhaust; the tell-tail is just to see if your pump is pumping as long as you get a steady stream of water coming out of the tell-tail; meaning not just trickling/steam! let it run and see if the temp. increases & increase the RPM's to see if she warms-up also there should be a slight to moderate increase of water coming out of the Tell-tail. good luck & let us know
 

NOLA26

Cadet
Joined
Feb 26, 2019
Messages
18
The motor is a 150 Saltwater series, I just noticed the typo in the original post. I do get water from the tell tail at a steady stream. The temp doesn't go over 140 so it doesn't appear to be overheating, but its just idling in the driveway.
 
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