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  1. #1

    Default 1971 Mercury 800 / lower unit

    I had someone put a new water pump in my mercury 80 hp well they didn't put it in forward position before taking off the lower unit. Well now I can't get it back in. What do I need to do in order to get it back in properly PLEASE HELP THANX ROGER

  2. #2
    Join Date
    May 2007
    Location
    Ireland,the only country in the world you can go North to go South
    Posts
    2,103

    Default Re: 1971 Mercury 800 / lower unit

    Drop lower unit,put unit and control into fwd.You will find three clicks close together in the unit,the left is fwd.Push unit up,rotate flywheel CW until drive shaft slides home.Bolt up.Remove plugs to turn flywheel if doing it yourself,and bungee cord to support unit helps.

  3. #3
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    16,683

    Default Re: 1971 Mercury 800 / lower unit

    And take all of the slack out of the lower shifter by turning it CCW. May times people miss that.

    Jeff

  4. #4

    Default Re: 1971 Mercury 800 / lower unit

    Quote Originally Posted by haventaclue View Post
    Drop lower unit,put unit and control into fwd.You will find three clicks close together in the unit,the left is fwd.Push unit up,rotate flywheel CW until drive shaft slides home.Bolt up.Remove plugs to turn flywheel if doing it yourself,and bungee cord to support unit helps.
    Thanks for the info I appreciate it. So can you please tell me what exactly is the reason for putting the unit in forward position before removing it? Thanks Roger

  5. #5
    Join Date
    Sep 2010
    Posts
    19,148

    Default Re: 1971 Mercury 800 / lower unit

    The clutch dog is spring loaded.--------It might / will jump into forward when you are not looking.------Then you might assemble and say " what happened " and pull your hair out.------Easy when you understand how it all works.

  6. #6

    Default Re: 1971 Mercury 800 / lower unit

    Quote Originally Posted by Scorpio4life2019 View Post
    Thanks for the info I appreciate it. So can you please tell me what exactly is the reason for putting the unit in forward position before removing it? Thanks Roger
    Well when I put the lower unit in forward position like you mentioned.it makes it so there is not enough of the spline showing that goes into the shift shaft. If that makes sense to ya?

  7. #7
    Join Date
    Sep 2010
    Posts
    19,148

    Default Re: 1971 Mercury 800 / lower unit

    That makes no sense at all .----The shift shaft turns and does not move up or down.-----But post pictures to explain this to me.----Note -----I own more than 1 of these lower units.

  8. #8

    Default Re: 1971 Mercury 800 / lower unit

    Quote Originally Posted by racerone View Post
    That makes no sense at all .----The shift shaft turns and does not move up or down.-----But post pictures to explain this to me.----Note -----I own more than 1 of these lower units.
    Ok I'll try to figure out just how to post pics. LOL here is the deal someone else took the lower unit off. Well they didn't put it in the forward position before pulling it. So now I'm stuck trying to figure it out myself. And I have been fukin with this thing for way too long. LOL

  9. #9

    Default Re: 1971 Mercury 800 / lower unit

    So do it in neutral: This is how I do it in about 60 sec.: Turn the LU shift shaft by hand counter-clockwise until it
    stops, then with Vise Grips tight on the bottom of the shaft turn it a
    few more degrees CCW until it clicks into a stop, this
    should be neutral - check by turning propshaft --
    prop should spin freely.
    Put control in N and go ahead and attach LU to driveshaft housing some turning of the flywheel will help the DS splines align.
    Do not shift into reverse unless you turn the prop at the same time.
    The shift shaft is about 3" long and 3/4" sticks up past the casing.
    Last edited by Quicksilver; 03-29-2020 at 12:33 PM.

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