how to check for lower unit leaks

Discussion in 'Bubba's Outboards' started by tbull, Dec 8, 2008.

  1. tbull

    tbull New Member

    Messages:
    3,318
    State:
    SW Ohio
    I know bubbakat told me what check i need to do with the LU on my outboard, I am just curious how to do it. If its a pressure check, do I need to submerge the LU, and pump air into it to check for bubbles?The lower unit is something I haven't fooled with much, but love to learn. How exactly do I conduct the test? I have water getting in and need to figure out where. Thanks all
     
  2. tbull

    tbull New Member

    Messages:
    3,318
    State:
    SW Ohio
    I went ahead and removed the LU, here are some pics its a mess in there.
     

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  3. tbull

    tbull New Member

    Messages:
    3,318
    State:
    SW Ohio
    One more
     

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  4. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    That ain't near as bad as some I have seen. You can fit the fill screw hole with a screw in type air valve and submerge the unit in water and add a little air and watch for bubbles. Now don't put over six pounds of pressure on it or you will blow seals every where, The drain and fill screw gaskets are the culprit most of the time.
     
  5. tbull

    tbull New Member

    Messages:
    3,318
    State:
    SW Ohio
    Do I need to buy some sort of special tool for that, I assume you cant use a normal air compressor? Is there a kit or something?
     
  6. tbull

    tbull New Member

    Messages:
    3,318
    State:
    SW Ohio
    Also what kit do I need to replace all these gaskets and seals? And should I go ahead and remove the gear case, berring carrier, etc...and check for damage, or just do the pressure test, replace the culprit and leave it as is. This thing really bumps hard sometimes when shifting into reverse.
     
  7. Bubbakat

    Bubbakat New Member

    Messages:
    4,532
    State:
    McMinnvill
    The fill and drain screw gaskets can be bought at about any marine outlet that sells and services boat motors. As for the other seals I would do the pressure test first and replace what needed to be replaced. As for the hard bump that is common so just put it into reverse or forward with a quick hard jump don't let the gears grind.
     
  8. tbull

    tbull New Member

    Messages:
    3,318
    State:
    SW Ohio
    what should I use to supply the air?...sorry I know these might be stupid questions just dont want to screw something up...:eek:oooh:
     
  9. katsandsuds

    katsandsuds New Member

    Messages:
    157
    State:
    North Caro
    You just need a small air pump or vaccum pump. You can get a vaccum pump from any automotive store, harbor freight, Northern tool, etc. I use a pump with a screw-in fitting to add lower unit oil. You can use that screw-in fitting and attach the pump tubing to that, pushing air into the fill oil hole with the rest of the lower unit sealed. The goal is to either push air into the lower unit, or use a vaccum pump and try to pull air out of the lower unit. Typically, they recomend pushing air in, but I don't have that type of pump, so I use a vaccum pump. if seals are leaking, the pressue will decrease quickly, and you can usually hear it if it is bad.

    The typical culprit is the drain or vent plug gasket on the lower unit which has already been discussed. I keep several of these on hand most of the time. Hope this helps.
     
  10. peewee williams

    peewee williams New Member

    Messages:
    3,111
    State:
    Pembroke,Georgia
    If you are not near a place to get the gasket,a "O" ring has got me by till I got the correct one.I got it from a farmer I saw.Many keep a "O" ring kit.

    White teflon pipe tape rolled and wrapped above the threads also work in a bind on many things.

    I would recommend that you look up Harbor Freight item 3878-5VGA and download the product Manual to check out.This pump pumps and sucks.It will pull out and put in oil out of holes and dipsticks without removing plugs or your rear end cover.It will pump Gasoline,other liquids,air or draw a fair vacuum.It has air fittings for tires.I found it to be a cheap ($5.99) and versatile pump.I have found many uses for mine.I store mine and the hoses in a wide mouth Dill Pickle Jar.
     
  11. catfish kenny

    catfish kenny New Member

    Messages:
    6,064
    State:
    Iowa
    Hey fellas Thank you for the lessons ...this is a valuable one!.