Can someone take a shot at this?

fishndvm

Petty Officer 2nd Class
Joined
Jan 4, 2003
Messages
125
I've posted with this problem previously with no resolution, but this time I've got pictures! I'd like to get her reassembled before it gets too cold out there.<br /> Short and sweet. I was given an engine by a buddy of mine recently...Merc 25hp XD. It was retired running perfectly, but rested for about ten years. I figured the first thing I'd do was to replace impeller. I pulled it apart, and disassembled the water pump. There was evidence of a sealant that had been used somewhere between the housing and the face plate, and although I cleaned it all off, I gave it no further attention.<br /> I bought an impeller kit, and when I went to reassemble the whole thing, I noticed that while trying to bolt the housing down to the face plate,the housing fit snugly to the plate on one half of it, but the other side did not. The housing is SS, and it is a combination of an inside cup (that holds the impeller) welded to the outer housing. The cup is not welded level, so when the housing gets bolted to the faceplate, the rim of the housing sits tightly against the plate on one side, but leaves a gap of several millimeters between the housing and the plate on the other side. Because there is an O ring gasket that fits in the channel formed where the cup is welded to the housing, I assume that a seal is supposed to be formed when the housing gets bolted to the plate. With the situation as I just described, this gap prevents a seal I presume. Also, when bolted down, the ends where the bolts pass through the housing get snugged to the plate, but but the gap in the middle remains.<br /> The best part is, becuse I assumed that there was a flaw in the manufacture of the housing, I bought a new one. Guess what? The new one is built EXACTLY like the old one! This does not seem quite right to me, but that's why I'm here. I need help. The following pictures will explain this perhaps confusing text. Thanks for your assistance. <br /> The first picture shows the housing from the top. <br />The second picture shows it from the bottom...cup welded within housing.<br />The third picture shows the rims of the cup and the housing level with eachother.<br />The fourth picture shows the opposite side, with the lip of the cup extending up above <br />the rim of the housing.<br />The fifth picture shows the level (even) side of the housing against the faceplate. They <br />meet nicely.<br />The last picture shows the opposite side of the housing against the faceplate, and you<br />can see the gap that results. The bolt holes are on either end, and you can see that if <br />you bolt the ends down, it will result in the ends meeting the plate, and the middle with <br />this gap. Is this normal? Again, the new part is manufactured exactly the same as this<br />one.<br />On the second picture, you can see where the inner cup and the outer housing come together. The channel formed here is where the relatively thin O ring gasket is supposed to sit. That gap that you see is wider than the gasket, so when the whole thing is bolted down, the gasket cannot really form any kind of seal where the gap exists. If this is meant to be, what's the point of the gasket? What do you think?<br />1. web page <br />2. web page <br />3. web page <br />4. web page <br />5. web page <br />6. web page
 

dolluper

Captain
Joined
Jul 19, 2004
Messages
3,900
Re: Can someone take a shot at this?

Throw a bead of high temp silicone on it and put it back together ....go boating
 

DHPMARINE

Captain
Joined
Dec 16, 2003
Messages
3,688
Re: Can someone take a shot at this?

I think some one discarded the 4 bushings (for the 4 bolts) that hold down the waterpump housing.This has distorted your housing.The Merc # for the bushings is #23-85095.$1.35 each.<br /><br />Good Luck !<br /><br />DHP
 

fishndvm

Petty Officer 2nd Class
Joined
Jan 4, 2003
Messages
125
Re: Can someone take a shot at this?

Hey DHP,<br /> Thanks for chiming in. I actually planned on replacing the bushings, but the reality is that I have the bushings, and they're actually in pretty good shape. Once the parts are lined up, all bolt holes aligned, the bushings fit in from the top. They pass through the housing perimeter, then through the face plate, and sit in depressions in the leg casting. The bolts then fit down through them. But unfortunately, the bushings don't change the situation. As a matter of fact, the bushings on the affected side must bear the extra force needed to compress the elevated portion of the housing to the plate. Nope. I just don't get it. Thanks for those numbers. I'll order them right away.
 

EZLoader

Chief Petty Officer
Joined
Sep 28, 2005
Messages
456
Re: Can someone take a shot at this?

I'd call Mercury and/or the parts supplier where you bought it from and have them explain it just so you know why it's designed that way.
 
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