Separating an outboard from its tilt mount...

Discussion in 'Outboards' started by CarbonFootprint, Nov 1, 2015.

  1. CarbonFootprint
    Joined: Nov 2009
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    CarbonFootprint Ill-Advised Boat Modifier

    Hello,

    I have a 1980's Johnson 115hp V4 2-stroke outboard on the back of my boat.

    As a general refurbishment, I want to replace the steering for the type that has a push-rod mounted through the outboard tilt-pivot tube.

    The pivot tube is old and rusty, though, and the threads at either end have had it, so the steering cable won't screw onto it.

    Presumably, I can get a new one (if I can find a part number - or just fabricate something new) but can anybody recommend the best way of splitting the engine and tilt-mount and then removing the pivot tube? It looks like it might be pressed in, so would a hydraulic press be the best way to get it out?

    Any help would be much appreciated,

    Thanks :)
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    I've never resorted to that, you can steer them happily enough off the steering arm, with the right set-up, you probably have that already. Maybe the workshop manual has instructions for that, though most people would never undertake that job, and neither would I unless it was absolutely necessary.
     
  3. whitepointer23

    whitepointer23 Previous Member

    I thought the tilt tube was secured with a nut at each end . Block the motor up and tap the tube out . A hoist to hang the motor on is best.
     
  4. Mr Efficiency
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    Mr Efficiency Senior Member

    He will have to destroy it to get it out, so better make sure he can get hold of a replacement part, or get one made, maybe mild steel would not be strong enough to make one. But they sure do rust well !
     
  5. CarbonFootprint
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    CarbonFootprint Ill-Advised Boat Modifier

    Hello chaps,

    thanks for your thoughts.

    At present, I'm thinking of hanging the engine on a hoist and trying to drift out the tube with a lump hammer and some blocks of wood - pretty much what you've suggested Brendan, so thanks for that.

    The OMC/Johnson/Evinrude workshop manual doesn't cover removing the tilt-tube, so it's obviously not an "everyday" sort of job, as you say Mr Efficiency :)

    The big nuts on the ends are there to stop it drifting left or right in service, I think, but the tube is well secured with them both removed, none the less.

    I might try taking the weight of the engine on the hoist and giving the tube an exploratory tap or two...what's the worst that can happen? :)

    Thanks :)
     
  6. whitepointer23

    whitepointer23 Previous Member

    Tilt tubes are easy to obtain new or used. The nuts are what holds it there, nothing else. Hit it harder it will come out . Or make a puller with a length of endless thread and some pipe.
     
  7. CarbonFootprint
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    CarbonFootprint Ill-Advised Boat Modifier

    Hi,

    the puller's a good idea - I think I'll go down that route, thanks!

    :)
     
  8. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    OMC sold a kit to remove them which was a puller like Whitepointer describes
     
  9. Mr Efficiency
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    Mr Efficiency Senior Member

    Point I was trying to make, once you undertake to remove it, it won't be re-usable, the thread would be shot probably. Best to have the replacement at hand before getting it out.
     
  10. CDK
    Joined: Aug 2007
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    CDK retired engineer

    The rusty tube may be very hard to remove unless you heat it with a welding torch before using the lump hammer or puller!
     
  11. Mr Efficiency
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    Mr Efficiency Senior Member

    Obviously it has to withstand the rigours of engine thrust and rough water, no doubt the reason stainless steel is not considered strong enough.
     
  12. Barry
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    Barry Senior Member

    I would be hesitant to take a welding torch to heat the casting as I suspect the housing is aluminum
    If it is you could buy a Temp stick, available from most welding stores, you heat the piece ( I would use a lower temperature propane plumbers torch) and CAREFULLY heat the casting. Keep touching the temp stick to the casting and when it is the right temperature the temp stick, wax, will melt and you will know that you are ok.

    When trying to separate aluminum from steel, I have used a plumbers solder flux. This soft flux has great capillary action and can wick into places extremely well with a little heat
    Of course you can get a penetrating oil, not WD 40, but an actual penetrating oil that has high capillary capability.
     
  13. CarbonFootprint
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    CarbonFootprint Ill-Advised Boat Modifier

    Hello all,

    thanks very much for all your replies - bowing to the common theme of what a nightmare job this will almost certainly be, I've decided to let discretion be the better part of valour and try to "refurbish" the tube in situ.

    What I really want to do is run a die along the thread that the steering cable is going to bolt onto, to make sure it's not going to bind and thread itself as it goes on.

    The pivot tube is part number 47 in this diagram - there are two nuts that screw onto either end of it, parts 44. The part number for this is 0323599.

    Can anybody tell me what the thread diameter/pitch is of these parts, please? I've measured the pivot tube thread at 22mm diameter, but being that the engine is US manufactured, I imagine this is actually an imperial size of some sort (UNC or UNF probably) and my measurement may be slightly off, due to rust and wear.

    Any help would be much appreciated,

    Thanks :)
     
  14. Barry
    Joined: Mar 2002
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    Barry Senior Member

    A die might not work as you will not be able to get the die up tight to the face where the nut bottoms out on the casting. The inside of a die is tapered so that as you are starting a NEW thread, the first tooth takes a little of material, then the next tooth a bit more and so on so that in order to get a thread cut, the die has to move beyond the area where the nut will go.( I am assuming a parallel thread not pipe)

    In other words, the teeth in your instance will not be cleaned up to the face of the casting

    Of course you can flip the die around as there is some thread now on your tube and run the die backwards which will get you closer

    Alternatively, you can use a thread chaser which is basically a hardened nut with a few grooves to permit the cuttings to fall out. This will clean up the threads almost to the casting face.

    It sounds like the threads are quite damaged so even if you clean them up, you might not have a secure thread.

    If you go this route and get an ok thread restoration, remember to Loctite the nut.
     

  15. gonzo
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    gonzo Senior Member

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