Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

davhen2311

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I have just been given an old johnson outboard which I want to do some work on. There is meant to be electric start as well as pull start but ignition block etc seems to be missing. Can I buy any key ignition block or does it have to be specific to this engine? Also how do i connect a battery. I will also be replacing fuel lines as the previous owner has done a bodge job.
 

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davhen2311

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Merging 3 posts from hijacked thread!

Merging 3 posts from hijacked thread!

I just picked one up too. the ignition seems to be missing, can i use any ignition with key? or does it have to be a specific one for this engine ? as I will have to have one shipped to Scotland from America if I go with genuine Johnson type. Also does anyone know how to wire the ignition up and how to connect a battery ? I would like to get the electric start fixed.
 

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Daviet

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

Are you trying to wire a remote start or a simple push button start?
It looks like the solenoid is already there, all you have to do is attach the positive battery cable to the other large post, the one with nothing on it.
Connect the negative battery cable to a bolt on the block, make sure you have a good clean connection.
Attach the wire from the ign switch or the push button to one of the small posts on the solenoid, and the other small post needs to go to a ground, usually through a safety switch.
Below is a wiring schematic from an older engine, take a look at it and see how everything is connected.
http://maxrules.com/graphics/omc/wiring/1957-60_35-40.jpg
 

davhen2311

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

Thanks for your reply
For now I would just like to wire up a push start switch or turn key type.
Can I fit a universal ignition switch off eBay or will it have to be the proper part from johnson?
 

davhen2311

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

I also can't find a kill switch. There is a white plastic block on the side of the engine with a black switch on the under side of it and not wired to anything but not sure what that is for yet.
Thanks for the diagram :)
 
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Daviet

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

Because of the mag ignition, you are going to need a marine switch.
Sierra makes a line of marine parts that are usually cheaper than OEM parts, if you look them up on line and get a part number, check with a local NAPA dealer as they usually sell Sierra parts.
 

davhen2311

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

I need part number 0383465 and have noticed that there is also a choke switch 0975257. Will I need the choke switch too or can I use the manual choke lever when using electric start? Can't seem to find the parts I need in the UK.
 

Daviet

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

You can manually choke the engine if you want to.
Can you post a picture of the white plastic block?
You can use a push button to start the engine and you would not need a key switch. If you go the push button route, you will have to install another push button to kill the engine, or choke it off, I suggest the kill push button.
 

davhen2311

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

Sure here it isDSC_0352.jpg

The push start and kill switches would be much better I think.
 

Daviet

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

Unless I am missing something, I don't see the white plastic block in the picture.
 

davhen2311

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

Sorry wrong pic I uploaded there. Here it is
DSC_0356.jpg
 

Daviet

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Re: Help with wiring ignition and connecting battery to 1973 40hp johnson outboard

That is a cut out switch. The black wire on the small center post goes to one set of points, if the engine over revs it will short out a set of points the keep the engine from blowing up. It is controlled by vacume.
 

bonz_d

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Re: Resto/Rebuild 1973 Johnson 40hp!

Re: Resto/Rebuild 1973 Johnson 40hp!

davhen thisn is a pretty old thread, it may be easier and better to start a new one.

Are you working on a remote or are you working on the enginens?
 

geoffwga1

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Re: Resto/Rebuild 1973 Johnson 40hp!

Re: Resto/Rebuild 1973 Johnson 40hp!

Have you checked the compression yet? that should be the first thing you do before spending ANY money on it.If that checks out,then move onto ignition and fuel system.When you have all that sorted you can start thinking about the lower end.Check for water in the oil,if ok and no leaks refill with fresh oil and move on to the water pump.Most times the housing is ok but check for wear on the pump plate,sometimes that needs renewing.First rule(mine anyway) "if it aint broke,don't fix it" but you won't know till you check.
 
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