OMC water pump question

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  • labrador-guy

    US Member - 2 Years
    Replies: 688
    Topics: 50
    #232123

    Guys I have been having a water pump problem on my 1957 18hp erude. It pumps water great at speed but at idle it sometimes quits. I have had it apart twice now changed the impeller twice and the grommets looked good. I was checking the water pump housing for wear and that looked good. I pulled the grommet for the water tube out and I noticed a mark on the side of the grommet. A small drilling was blocked by the grommet. Maybe there is a shorter grommet? I don’t know. Do you guys think this drilling in the housing being blocked could be my problem? Engineering put the hole there for something! Maybe the pumps need water on the top to make it work? Anybody have experience with a problem like this. Pictures coming!

    dale

    “There are three kinds of men. The ones that learn by readin’. The few that learn by observation. The rest of them have to pee on the electric fence for themselves!” WR

    What is this little drilling for?

    I cut the Grommet to uncover the hole.


    frankr

    US Member - 1 Year
    Replies: 6181
    Topics: 49
    #232136

    That hole is drilled at an angle, connecting the water outlet to the well surrounding the drive shaft. The purpose is to keep the well filled with water, creating a water seal to prevent exhaust gasses from entering the pump via the drive shaft hole. The UPPER end of the angled hole will be blocked by the grommet, but the LOWER end of the hole should not be blocked. If blocked, it may cause erratic pumping.


    frankr

    US Member - 1 Year
    Replies: 6181
    Topics: 49
    #232137

    Found my picture

    Water-pump-housing-bleed-hole


    Mumbles

    Canada Member - 2 Years
    Replies: 5507
    Topics: 292
    #232146

    Here’s another view showing how that hole is drilled on an angle. It and the small bleeder hole at the bottom of the well must both be clear and open for the pump to work properly.

    DSC00003


    billw

    US Member - 2 Years
    Replies: 1758
    Topics: 53
    #232154

    I have had a few cases where I had deemed the pump housing good enough, as the engine was pumping okay before service…..but then would not pump well at idle with a NEW impeller. The trouble is, the old housings and impellers wear together and fit like a glove, in some respects. A new impeller doesn’t fit into the old wear pattern as well. Changing the housings to new ones solved my problems astonishingly well. I guess this was me, peeing on the electric fence, right? By the way, what is going on with the bottom of your grommet? It looks torn up somehow, in the picture.

    Long live American manufacturing!

    • This reply was modified 1 year, 4 months ago by billw.
    • This reply was modified 1 year, 4 months ago by billw.

    labrador-guy

    US Member - 2 Years
    Replies: 688
    Topics: 50
    #232157

    I have had a few cases where I had deemed the pump housing good enough, as the engine was pumping okay before service…..but then would not pump well at idle with a NEW impeller. The trouble is, the old housings and impellers wear together and fit like a glove, in some respects. A new impeller doesn’t fit into the old wear pattern as well. Changing the housings to new ones solved my problems astonishingly well. I guess this was me, peeing on the electric fence, right? By the way, what is going on with the bottom of your grommet? It looks torn up somehow, in the picture.

    • This reply was modified 1 year, 4 months ago by billw.
    • This reply was modified 1 year, 4 months ago by billw.

    Some people gotta learn the hard way! me too! I cut the bottom of the grommet so it won’t plug off the small drilling in the housing. I think that will fix my problem. Wonder how many other motors around are messed up? Those pump housings are getting harder to find lately.

    dale


    crosbyman

    Canada Member - 2 Years
    Replies: 2777
    Topics: 273
    #232161

    the new pump housings on Amazon don’t have those holes ??? Mumbles… did you ever install the cheap ones ($25) you picked up before all of us 🙂

    is it because “the well filled with water, creating a water seal to prevent exhaust gasses” is not molded / needed like the original pumps ?

    Joining AOMCI has priviledges 🙂

    • This reply was modified 1 year, 4 months ago by crosbyman.

    fleetwin

    US Member - 2 Years
    Replies: 4246
    Topics: 42
    #232163

    OK, so these hsgs have “two” bleed holes (not including the end of the hole covered by the grommet)? Funny, how the grommet in your picture looks kind of long, but I’m thinking it is just the camera angle.
    Nonetheless, I agree with Bill’s comments. Wear in the aluminum impeller housings is often over looked. I remember servicing 6hps in out test tank. The engines would pump fine in forward gear, but kind of fade away if in neutral or run in reverse for a few minutes. This scenario kind of makes sense because the movement of water in forward gear produced some added pressure which helped the pump work even with worn hsg/impeller plate.
    Has anyone actually ordered one of those Amazon pump kits pictured here? Wondering if it is actually an OMC/BRP part, or chinese knock off…The color of the gasket makes me think it is not OEM.
    Let us know how you make out with this water pump situation…


    crosbyman

    Canada Member - 2 Years
    Replies: 2777
    Topics: 273
    #232164

    I got one but not at $25 like Mumbles did …. the price shot up after they woke up on the pricing error !!

    mine was 70$ CDN free delivery….. and the $48 ones are cheaper but when delivery is added on they end up $70

    I have not installed it yet … I am certain they are chineese copies at least the gasket should hold up ( orange carb gaskets apparently melt and ooze…. 🙁

    Joining AOMCI has priviledges 🙂


    frankr

    US Member - 1 Year
    Replies: 6181
    Topics: 49
    #232167

    Crosby, are you sure there are no bleed holes in the new housing? I don’t have one to look at, but I do have this OEM one which I think is for a 35hp. They went out of their way to deal with the shaft hole. First, they added a seal, then they also added a slot between the outlet tube and the area between the the plastic housing and the stainless cup.

    bleed-slot


    Mumbles

    Canada Member - 2 Years
    Replies: 5507
    Topics: 292
    #232179

    It looks like the rain is going to letup soon so as soon as it does, I’ll go out and compare an OEM pump kit to a Chinglish one.


    Matthew Pieklik

    US Member - 2 Years
    Replies: 73
    Topics: 34
    #232184

    Call Websters , we have a new word to put in the book. Chinglish


    Mumbles

    Canada Member - 2 Years
    Replies: 5507
    Topics: 292
    #232194

    Well, I compared the OEM 763758 and the $21.29 Amazon water pump kits and found a couple things different between the two. The parts in the Chinglish kit are all individually wrapped and sealed. Not so for the BRP kit. The impeller drive pin in the Chinglish kit is also knurled, which keeps it tight in the driveshaft. Two stars. The two kits seem identical in every way except the OEM kit has aluminum inserts in the housings screw holes and the Chinglish housings have brass inserts, which I prefer. Aluminum and salt don’t mix very well so that’s one more star for the offshore pump. The OEM liner has small manufacturing indentations in it on either side of the bleed hole while the Chinglish one is perfectly smooth and the OEM wear plate was scratched a bit straight out of the box. Two more stars for the offshore pump. The impellers were cold so it was hard to see if one was more pliable than the other but they both felt the same. The impellers, liners, and gaskets all measured the same so I don’t really think one kit is much better than the other except for the price but I am tending to favor the Amazon kit.

    DSC00034

    DSC00036

    DSC00038

    DSC00039

    DSC00040

    DSC00041

    DSC00035

    • This reply was modified 1 year, 4 months ago by Mumbles.
    • This reply was modified 1 year, 4 months ago by Mumbles.
    • This reply was modified 1 year, 4 months ago by Mumbles.
    • This reply was modified 1 year, 4 months ago by Mumbles.

    crosbyman

    Canada Member - 2 Years
    Replies: 2777
    Topics: 273
    #232203

    FR… I looked closely at my pump and there is a small hole in the stainless cup which lines up with a surface cavity, sending any pressurized water o the shaft area just above the SS cup

    so that said it looks like water will reach the rotating shaft cavity while 99 % of the pumped water will go up the water tube 🙂

    Problem solved… good eyes 🙂

    Joining AOMCI has priviledges 🙂


    crosbyman

    Canada Member - 2 Years
    Replies: 2777
    Topics: 273
    #232204

    mumbles beat me by 3 minutes while I was typing 🙂

    Joining AOMCI has priviledges 🙂

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