changing water pump/50 merc. /2 stroke

[Kenny Guess]

I am going to change my water pump soon. When doing so, do I leave motor in neutral to drop lower unit or in forward gear? This is a 2004 50hp 2 stroke Mercury. Thanks, kenny

 

[Larry Harp]

I did this on a 50 hp a year of so ago so I'm trying to remember. On mine, a 2001, there was a small shaft that was on the forward side of the LU. It has two nuts that you have to loosen to separate the shaft. In order to get the nut in a position to get a wrench around it you have to put the LU in gear. That's how I did mine. I left it in forward and had no problems. I don't think there's an issue with leaving the LU in gear or neutral. I don't believe there's any timing or anything like that to worry about and you have to giggle with the prop a little to get the splines to line up anyway. Somebody who has a lot more experience than I may have a different opinion.



Actually I did have one problem that was the result of how my helper re-assembled the water pump. I didn't replace the whole pump, just the impeller. There are two Nylon washers that go on top and bottom of the impeller. He put the thing back together with the impeller and the washers in the pump housing before he put it on the shaft. When he put the pump on the shaft one of the Nylon washers got bunched up which let the key come out of the keyway. It obviously didn't work right. I put it back together (without help this time ) and put all the parts on the shaft first and then put the pump housing over the impeller. You have to turn the impeller while you slide the housing over it. All this information may not apply if you're replacing the whole pump assembly, I don't know how they come.

Hope this helps.



Good Luck!

Harpo

 

[Drew Dennis]

Check your MSN email... NM it bounced back. PM me a good email address..preferrably a Gmail address. I have a 14meg file for you..

 

[Tommy Hayes]

How often should you change your water pump? I have the same engine in a 2006.

 

[Kenny Guess]

I completed the water pump change on the 50 Merc. in less than an hour ! It was very easy for those that are not sure if they should have someone do it or try it themselves. The hardest thing was to have a place to set the lower unit up as you exchange parts , I happen to have a wood vise that worked great. If you have a metal vise, just put two pieces of one by lumber in the vise and clamp the skeg in between-presto ! Then take your time and exchange parts...just watch how each piece comes off - only 7 pieces - the flat metal plate, 2 nylon washers, 2 gaskets , the impella and the conection between the w. pump housing and the return hose to the top. The kit cost $51 from my local Merc. dealer and if you want to replace the housing, it is $ 61 but mine was fine. You will need the necessary metric tools of course. Took it out today and it is pumping with gusto !! Actually the original impella was in very good conditon and would have done fine for a few more years but as they say, it is a good thing to change it every 3 years. And the big thing for me is I now know how to take it down and have a look anytime something doesn't seem right. If anyone has any questions on this procedure that I didn't mention, email me - if I can help or answer anything, I will. Kenny