40 HP Mariner Impeller Replacement

Discussion in 'Bubba's Outboards' started by Spills, Oct 25, 2007.

  1. Spills

    Spills New Member

    Messages:
    61
    State:
    Missouri
    Thought I would put up some info and pics on replacement of an impeller. This is on a 40hp Mariner. From what I understand this was built by Yamaha to Mercury specs, which is fine with me except finding parts has been a pain...:angry:. We dropped the lower unit last night, and had an impeller replacement kit, which of course turned out to be the wrong one. I think we've found the right one and ordered it last night.

    Here's a run down of what we did:

    Drain lower unit first...unless you want a mess.

    There are 6 bolts holding the lower unit on. I would suggest removing all but one in the center. Once you've done that there is a screw holding the shift rod in place in the lower unit. Remove that screw, then the final bolt holding the lower unit on. The shift rod has a rubber boot on it that slides into a tube, this will catch if you just try and pull the lower unit off. There is a single bolt holding the plastic tube in the lower unit, take that off, and the unit is now free it should drop right off. There are four bolts for the impeller housing, remove those, and with a little encouragement the housing should break free from the gasket. Ours was sealed on there pretty tight.


    Here are some pics of what the impeller looked like when we cracked it open. Pretty worn.
     

    Attached Files:

  2. Spills

    Spills New Member

    Messages:
    61
    State:
    Missouri
    Here is some additional pics of the impeller replacement. I'll get some more up when we get the kit in, and finish this. Also there is a pic of the bolt that you need to remove for the shift rod on the lower unit, it's highlighted in yellow.
     

    Attached Files:


  3. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    From the looks of your pictures, you lower unit is similar to most lower units. In that regard, you do not need to drain the gear lubricant unless your going to service the lower unit irregardless.
     
  4. tofish

    tofish New Member

    Messages:
    3,923
    State:
    arizona
    i was just gonna ask the difference between a mariner and a johnson or merc motor. never had to drain either of those lower units to change out impellors.
    from looks of that one, good thing you stopped running when you did. my last one just blew apart. working great, then suddenly, done. one fin left out of 4 when i pulled it apart. had to float down about 3 miles of river to get to launch ramp, and not one fish would bite the whole darn way. :angry:
    gary
     
  5. Spills

    Spills New Member

    Messages:
    61
    State:
    Missouri
    This was the first time I've ever removed the lower unit, so I wasn't sure if i needed to drain it or not, I did just to be sure I wouldn't have a mess all over my workbench. Plus I have no idea when the last time this thing was serviced so I figured it couldn't hurt to put some fresh lube in there. Thanks for the info guys.
     
  6. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    This is a good illustration you are putting together here. In the fact that the impeller was missing some rubber bits. I hope you found all of them if not then they could be lodged up in the block. Some times you can take a hose and flush the bits out by pushing it up through the pick up tube.
    While you are changing the lower unit oil add the new gaskets under the fill and drain screws. Its always good to change the oil when installing a new pump. You did install a complete pump didn't you? That wear plate was worn out.
    If this is your first one you are doing OK in my book.
     
  7. Spills

    Spills New Member

    Messages:
    61
    State:
    Missouri
    Thanks for the tips about the pieces of the impeller. Yes I am replacing the entire unit, new gaskets, plate, etc.. I'll see if I can find the rest of the pieces. Some of them were on the impeller hanging by a thread, and a few were loose in the housing. I'm just waiting for the right parts to arrive, then I'll put up some more pics. Thanks for your help fellas.
     
  8. Spills

    Spills New Member

    Messages:
    61
    State:
    Missouri
    Looking for some help. We put in the new impeller, fired it up, but we're not getting water flow. Had it hooked to the muffs, and let it run for about 30 seconds, but never saw water, so we shut it off. We took the lower unit back off, and made sure the impeller is turning with the drive shaft, and it is, water tube appears to be lined up...any suggestions?
     
  9. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Try lowering it into a tub of water and see if it helps.
    The last time I had that problem with a merc I had to replace the lower part of the pump housing. That and the pickup tube is about the onlything left that would stop the water flow unless part of the impeller vanes are up in the head.
     
  10. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    Had that problem on a 50 HP Johnson. Removed and re-stabbed the lower unit about 5 times before we finally got the water tube in the right position. It would look perfect until the final 1/2 inch, then would just get nudged to the side by the lower unit. Frustrating, but not hard. LOL
     
  11. Spills

    Spills New Member

    Messages:
    61
    State:
    Missouri
    Well we got it working finally. We just didn't have enough water flow, the first set of muffs we had were crap, got another set that were much tighter, and sealed nice, that did the trick. We took it out yesterday, and it ran better than it ever has.
     
  12. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    Thanks for the follow up Jon.