Mercury KD4

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Viewing 15 posts - 121 through 135 (of 140 total)

  • green-thumbs

    US Member - 2 Years
    Replies: 473
    Topics: 38
    #236233

    Removing and installing crankshaft/reed block is not difficult if you
    have a press or can fabricate a substitute. There are a few things to
    keep in mind to do it right. I will dig up photos that will explain process
    Bear in mind that to get to point where crankshaft can be removed involves a complete disassembly of powerhead. Upper and lower seal
    can be changed without taking powerhed to pieces. Most of the motors
    I have came as rusted, busted, or stuck or all 3 so full rebuild was a given. If you like wrenching that is not a problem,
    Louis
    Pressing crankshaft/reed block in or out of crankcase involves a lot of force applied to crankshaft. To avoid springing the crankshaft install nut and bolt jacks between cheeks of crank throws. I use 1/4×20 bolt
    and nut jacks turned snug ,but, not to tight.

    Sharp eyes will notice crankshaft is from KE4/Mark 7. which has a thinner reed block and 4 reed petals,

    • This reply was modified 6 months, 1 week ago by green-thumbs.
    • This reply was modified 6 months, 1 week ago by green-thumbs.
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    Boonie

    Canada Member - 1 Year
    Replies: 147
    Topics: 14
    #236241

    Thanks Louis. Is this procedure necessary to replace the crank seal?


    dave-bernard

    US Member - 2 Years
    Replies: 1468
    Topics: 18
    #236244

    NO !


    opposedtwin

    US Member - 2 Years
    Replies: 860
    Topics: 240
    #236246

    NO !

    Dave,
    How do you remove that upper crank seal without removing the shaft?
    Does mercury have a special tool for this procedure? I have a seal remover for OMC upper crank seals and it works very well.

    Scott


    Buccaneer

    US Member - 1 Year
    Replies: 5085
    Topics: 831
    #236249

    It appears to come out the bottom of the crankcase.

    KD4-Powerhead

    Prepare to be boarded!

    Attachments:

    Boonie

    Canada Member - 1 Year
    Replies: 147
    Topics: 14
    #236255

    Yes it does. But I can’t see going thru all of that just to change the upper crank seal!


    Boonie

    Canada Member - 1 Year
    Replies: 147
    Topics: 14
    #236285

    So I can remove the seal with crank still in the engine case? Just try to pry it out?


    green-thumbs

    US Member - 2 Years
    Replies: 473
    Topics: 38
    #236299

    Upper seal can be removed by drilling 2 small holes on opposite sides of the seal, screwing 2 sheet metal screws and prying the seal out, If screws pull out drill 2 more holes and repeat,
    Mercury part # for seal is 26-21642
    C/R seal 7415 will work
    Be sure to lube seal and crankshaft when installing new seal to avoid
    damage to seal lip.’

    It isa good practice to have 7/16″x20 fine thread nut on
    crankshaft when working on powerhead to prevent damaged thread.
    Before using a nut for this purpose, run a tap thru the nut to be sure
    the thread us good, As a part of preparing a powerhed for assembly
    it is an excellent practice to run die over all threads and a tap thru
    all nuts and threaded holes. Picky Picky, but very often needed,
    Louis

    • This reply was modified 6 months, 1 week ago by green-thumbs.

    Boonie

    Canada Member - 1 Year
    Replies: 147
    Topics: 14
    #236303

    Thanks Louis. Ordered new rings from Poole yesterday. When they arrive the assembly will begin.


    green-thumbs

    US Member - 2 Years
    Replies: 473
    Topics: 38
    #236323

    A bit more about removing and installing crankshHaft/reed block assembly
    1) Nut and bolt jacks are installed thru openings on either side of carburetor opeing. Cover plate has to be removed
    2) Bolt in side of crankcase screws in to reed block. Remove before pressing and replace after crankshaft is installed.
    3) When replacing reed block on crankshaft the screw hole and carburetor passage have to line up,,,
    4) Small hole in reed block is key to aligning reed block so that
    thread in reed block and bolt hole in crankcase are spot on.

    • This reply was modified 6 months, 1 week ago by green-thumbs.
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    green-thumbs

    US Member - 2 Years
    Replies: 473
    Topics: 38
    #236666

    With reed block/center main bearing assembled to crank shaft and jacks in place time to press assembly inot crank case.
    Check that intake passage and thread hole in reed block will align with
    respective openings in crank case…if not reed block is on upside down
    Fit the assembly into crank case and use 1/16″ drill bit to clock the
    reed block if the drill is 90 drees to face of crank case, thread in reed block and hole in crank case will line up,
    Remove drill bit!
    Press carefully until indicatorn hole in reed block just begins to show
    Then check how thread and hole,
    At this point very slight pressing to arrive at SPOT ON!
    If you get it right the bolt can be screwed into the reed block thread
    without contacting side of hole in crank case.
    A bit of lube on all points of friction and care in aligning with drill bit
    will get it right the first time every time.
    When all is checked and satisfactory remove jacks.

    Sharp eyes will notice this is a KE4 not a KD4…same techniques
    apply for both.
    90 degrees can be eye ball close enough or a simple gauge can be made to clock the reed block.
    I use a 12 ton HF press and some odds and ends made or adapted to
    press crank shafts out or in, for a one off job a couple stron boards and
    a pair of nut washer and threaded rods would work,

    Until I understood the reason for the small hole in reed block I did a lot
    of trial and error installing crank shafts. Sometimes I could get it right
    the first time and at other times 2 or more attempts were needed,
    The hole is present on 1940 K4 and all twin reed block/center main bearing… (1940 twins use external reeds while 1941 and later have
    reeds untegrated into center main bearing.

    Attachments:

    Boonie

    Canada Member - 1 Year
    Replies: 147
    Topics: 14
    #236676

    Does anyone have torque specs or ring gap info for the KD4 power head? Preferably ring gap and connecting rods.


    green-thumbs

    US Member - 2 Years
    Replies: 473
    Topics: 38
    #236718

    Rod cap screws 90 INCH pounds
    rule of thumb is 0.004″ per inch of bore diameter
    Opinions will vary,
    Flywheel 40 FOOT pounds
    Reed Valve 30 INCH pounds
    12 INCH pounds equal 1 FOOT pound
    Spark Plug…finger tight plus 1/6 turn to compress NEW gasket.
    Or 15 FOOT pounds
    No specs given for other fasteners which all use lock washers of one type or another.
    Louis


    green-thumbs

    US Member - 2 Years
    Replies: 473
    Topics: 38
    #236801

    Early K Model twins differ in many details. Tools and technique to tear down and rebuild are much the same 1940 Mercury K4 through 1950sWizard WG4.

    Sharp eyes will notice arm of upper water jacket has been repaired A big Thank You to good guys in chapter, Also of note is use of hex socket head screws to secure water jackets, cyliners to crank case…use what you have to get job done.

    Last photo…primed parts await a warm calm day to paint,

    Attachments:

    Boonie

    Canada Member - 1 Year
    Replies: 147
    Topics: 14
    #237421

    Green thumbs. So on a 2” bore ring gap should be 0.008”?

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