KG7 Water Pump Cover Removal

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    bkrsdoz

    US Member - 1 Year
    Replies: 70
    Topics: 6
    #191254

    I have a fairly clean 1951 KG7 and am having trouble getting the water pump cover loose.
    I have the factory tool, been soaking it with acetone/ATF, have also tried some heat around the foot casing.
    I know it is a right hand thread, so “tighten to loosen”.
    I have a 16″ wrench pulling on the factory tool, and broke one of the pins off the tool.
    I have replaced the broken pin with a 3/16″ drill bit shaft.
    Any ideas would be greatly appreciated.
    Thanks!
    Bob

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    dave-bernard

    US Member - 2 Years
    Replies: 962
    Topics: 12
    #191268

    call me 1 914 310 7086

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    joecb

    US Member - 1 Year
    Replies: 354
    Topics: 59
    #191312

    If it’s “tighten to loosen” then it’s called a LEFT hand thread.
    For the benefit of educating us “non – Merc” guys. Please come back with the rest of the story once you get it apart.

    Joe B

    labrador-guy
    labrador-guy

    US Member - 2 Years
    Replies: 254
    Topics: 29
    #191313

    bkrs, your not getting much response from the Mercury guys! Dave will fix you up, he knows his stuff. I have first hand experience with that dirty sonofagun cover that you are working on! Old Carl got SOB several times before I got mine off. I tried heat several times. Every kind of penetrating potion that I could find. I tried to melt wax into the treads. Hammered the case on both sides. Then I went nuclear! Ya get to a point where its gonna come apart or throw the darn thing it the trash! I built two different tools and I kept breaking the pins off or bending them so bad they wouldn’t stay in the holes. I drilled the darn thing out! Literally, see the pictures! Hope you find a better way.

    dale

    Long drill

    Almost there

    Victory!

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    frankr
    frankr

    US Member - 1 Year
    Replies: 4660
    Topics: 45
    #191330

    Pardon me while I sit here and smile. I used to work on those things back in “The Day”. At the most, I may have seen three or four that would come apart with the special tool. All the rest got drilled out. I drilled them in a different pattern than you did, but the idea is the same. OK, so I admit they were all salt-water exposed.

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    garry-in-michigan

    Lifetime Member
    Replies: 3506
    Topics: 31
    #191366

    After drilling them out (I used a different patern) and cleaning up the threads, I always wrapped the new cover with teflon tape. It made a better seal and was easier to remove the next time , , , Karl used a left handed thread so the rotation of the prop shaft would keep them from unscrewing – LOL

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    dave-bernard

    US Member - 2 Years
    Replies: 962
    Topics: 12
    #191368

    wont unscrew. the prop direction is the same as tightening.

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    green-thumbs

    US Member - 1 Year
    Replies: 328
    Topics: 35
    #191400

    Some years back Bob Grubb shared a technique he used…using hammer and punch (not too forcefull) tat tap tap around
    the gear case over the area of where cover threads into
    case threads. To avoid dimpling I have used aluminum bar stock
    A friend demonstrated use of propane torch to cook the
    gear case…I can still smell the hot grease.
    I have used the Mercury Service Tool and even found a cover
    that would come off as shown in service manual.
    Once off, clean the threads in gear case and on cover and apply
    suitable lube to threads. It is not necessary to install cover
    tight as the friction of ruvver impeller and prop shaft tend to
    tighten not loosen the cover.
    Often cover shows signs of having been removed by use of hammer
    and punch in the pin holes, Once the pin holes are damaged
    the correct service tool may not engage well enough to remove
    even a slightly stuck cover. Drill bits make good replacement pins
    however, not all drill bits are equal..low grade steel drills are weak
    and will bend. I have found Dremel cut off disc will slice thru even
    grade 8 bolts and best quality drill bits.
    The cover is LEFT HAND (counter clock wise) 2 1/8 ” x 14 threads
    per inch A basic lathe task to make a replacement, but, fairly
    time consuming to make on a one off basis.
    I have not done a lot with the later Green Mercurys, just enough to
    know they are more complex than KE3 and prior K Models
    If you get the cover off intact despite damaged pin holes, a new
    set can be drille 90 degrees away. Takes some careful doing, but,
    price out a replacement cover and think about it.
    Louis

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    oldcollector

    US Member - 1 Year
    Replies: 15
    Topics: 7
    #191668

    I also worked on this style many years ago with the same problem. Our answer was to take a hole saw just a little smaller than the pump cover,and weld it on the end of a pipe that was just a little larger in diameter than the drive shaft diameter, and longer than the driveshaft plus the thickness of the water pump cover, plus about one inch , then cut off one end of an old large allen wrench ( about two inches long ) and weld it on the upper end. Making sure to leave enough room for the drive shaft length plus the thickness of the water pump cover inside the pipe. try to make it as strait as possible,and don’t turn it to many RPM when cutting out the pump cover. Oh ! leave about one inch of the allen sticking out of the pipe to attach your drill motor.

    labrador-guy
    labrador-guy

    US Member - 2 Years
    Replies: 254
    Topics: 29
    #191772

    oldc, I like your idea! The hole saw turning right hand might back the bugger out before it was cut all the way through. If I ever get another one, no that’s not gonna happen!

    good idea
    dale

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    green-thumbs

    US Member - 1 Year
    Replies: 328
    Topics: 35
    #191799

    Be gentle, any method that preserves the thread in gear case is a good method AND any method that messes up the gear case thread is BAD.
    The cover is stuck either because it was installed tightly OR because
    threads are corroded…most likely corrosion ,which may mean the
    thread strength is compromised. Some combination of heat, solvent
    and percussion may unlock the corrosion locking cover thread to
    gear case thread allowing the cover to be worked loose and removed,

    A cover with clean thread and a gear case with clean thread (both
    greased) can be installed and remove with only finger pressure,,,no
    special tool needed. The difference between the effort needed to remove a stuck cover and a cover that is easily turned has to be
    either the force used to install it or corrosion, If you are going to have
    a replacement cover made the old cover can serve as the pattern
    to follow in machine the replacement. Easier if the cover is intact not
    in fragments.
    Gear case and covers for KE4 thru KG4 vary in some details ,but, share the same thread. and same problems.
    Louis
    .

    • This reply was modified 1 week, 3 days ago by Avatargreen-thumbs.
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    bkrsdoz

    US Member - 1 Year
    Replies: 70
    Topics: 6
    #191891

    I had soaked and heated the cover for several days.
    I clamped the tool on so it could not ride up on the holes in the cover and slip.
    Both pins snapped off clean on the tool, and the cover didn’t budge.
    I will reluctantly drill out the cover as suggested, and collapse the remnants and remove it the hard way.
    I now recall why I really like the vintage Johnson’s and Evinrude’s!
    There is nothing quite like a KG7 whining on the back of the boat though!
    I’ll keep at it and will be successful.
    Thanks for the photos and suggestions.
    Bob

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    green-thumbs

    US Member - 1 Year
    Replies: 328
    Topics: 35
    #191925

    Be gentle and patient. ‘
    Louis

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    jeff-register

    US Member - 1 Year
    Replies: 1138
    Topics: 48
    #191967

    Righty tighty…..NOT Lefty tighty Righty lucy
    I used steam fitting anti seize joint compound on the threads.

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    pugsmanias

    US Member - 1 Year
    Replies: 4
    Topics: 4
    #192126

    I’ve had to do that! Even with all the correct tools I have, sometimes you have to get medieval on it. Anti-Seize is a great suggestion.

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