Johnson 1970 85hp electrical conversion

Discussion in 'Outboards' started by Joshi4365, Oct 23, 2018.

  1. Joshi4365
    Joined: Oct 2018
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    Location: Australia

    Joshi4365 Junior Member

    Hi all just wondering if it is possible to convert the ignition gear on my 1970 85hp to the same style as the 1973 models? I have purchased a whole ignition set but its for a 73 on has anyone done this? Is it a simple swap over?
     
  2. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    Are they both CD ignition ?
     
  3. Joshi4365
    Joined: Oct 2018
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    Location: Australia

    Joshi4365 Junior Member

    Yeah but one has the coil all 4 coils in one unit (1970) and the other set off the 73 has individual coils first pic 70 model second later models 42037.gif 42447.gif
     
  4. Mr Efficiency
    Joined: Oct 2010
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    Mr Efficiency Senior Member

    So you have the complete ignition system componentry ? I am wondering if the flywheels might be different ? You could check the part number for that for each year model.
     
  5. Joshi4365
    Joined: Oct 2018
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    Joshi4365 Junior Member

    Here is what I purchased. I will Check the flywheel numbers now. s-l500.jpg
     
  6. Joshi4365
    Joined: Oct 2018
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    Joshi4365 Junior Member

    The part no's appear to be different so if i got the flywheel could it be done?
     
  7. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    I have had versions of that motor, not that early though. One assumes the flywheel with its magnets, is matched to the stator assembly. Do the mounting points for the stator look the same with both systems ? Are the mounting points for the other ignition bits and pieces the same, so that you can just screw on the replacements ? This is a bit of a complicated operation, the spark advance components might be an issue as well. If the cranks are the same, presumably you can swap the flywheel, but if the tapers are not the same, or the keyways are different.....you get the picture. Modern outboard shops would not want to know about these old things, most would have no experience with 45-48 year old engines, so I doubt you will get much help there. These are old motors now, I would suggest you try a website where they like to talk old outboards, although these are not quite "vintage".
     
  8. Joshi4365
    Joined: Oct 2018
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    Location: Australia

    Joshi4365 Junior Member

    I downloaded A manual for 1970 115hp motor which are very similar just not the timing/tuning as for the conversion I think i'll send the parts I bought back and just buy a new CDI set which the amplifier seems swollen so I am guessing thats where my issue is but i am yet to hook up the battery and try I bought the boat and motor for $250 and was told there was no spark. Anyways thanks for your help I will be sure to drop you a line if I have any other queries. Thanks.
     
  9. Mr Efficiency
    Joined: Oct 2010
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    Location: Australia

    Mr Efficiency Senior Member

    You can test all your ignition components with a simple multimeter, but you will need the workshop manual that covers your particular engine, and just follow the instructions therein re testing the bits and pieces, otherwise it is a tiresome and expensive guessing game. That will tell what is shot, or not, and is a relatively easy task. You should always get a manual before working on any outboard. The manual for the 115 V4 should be right to test those components with the multimeter.
     
    Last edited: Oct 23, 2018

  10. powerabout
    Joined: Nov 2007
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    Location: Melbourne/Singapore/Italy

    powerabout Senior Member

    have you tried it?
    You might have to change the crank top bearing housing to mount the new style timer base, flywheel for sure.
    Personally I would be looking for a 73 or later complete engine, 79 on even better
     
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