[Lairddog]

Hey, my 1986 Mercury 50 hp engine won't pump water. I just replaced the water pump (correctly) and it still won't pump water. Any ideas or recommendations?
Thanks!
LairdDog

[achris]

Check to see if the pump is sucking water... If it is, then you may have missed the water pipe when you put the leg back on, it's easy to do!

With the flushers on, turn the tap on until there is a little bit more flow than the engine normally draws. Watch the flushers while some else starts the engine. You should see a noticeable drop in the amount of water coming out of the side of the flushers. That indicates the pump is pulling water.... Now all you gotta do if find out why it isn't getting to the powerhead. Or is it.... How long did you leave it running? It can take a bit of time for the engine block to fill before the water starts coming out of the telltale.

Chris............

[Nandy]

I missed the pump intake tube when I changed the pump for my rude for the first time. Im used to my mercury that aligns perfectly, not so the rude. I bet that is your problem.... Dont let that motor run for long without proper water intake. Good luck.

[Boatleech]

Are you sure it's not pumping water, or is there just no water coming out the telltale? Sometimes the telltale clogs (mud daubers, etc.) and it looks like the pump quit.

[Nandy]

Whoa, read you post again, initially I thought it stopped working after you did the impeller change but now Im not sure what you meant. Was it not working at all before you made the impeller change? If it was not working before double check the port. I have had mud daubers before and other type of restrictions where the pump was working fine but the telltale will not put water out. Good thing is that even if you dont have water coming out of the telltale and the pump is working it will not hurt your motor.
If the telltale port and hose are clean and you are sure your pump and water intake is correctly aligned then obviously there is something wrong. I made an attachment for the mercury so I could run it without the lower unit. I got a clear hose from home depot that fit the water intake and then fit it with a connector so I could get the garden hose to it. I secured the clear hose to the intake and open up the hose. Even with the motor off you should see the water coming out of the telltale. Needless to say, if that works then the problem is in the lower unit, if that dont work then there is a restriction somewhere in the water jacket of the power head. Hopefully it will not get to that. Good luck!