Wiring - 1961 Johnson RDSL-23 40HP & 1958 LoneStar Malibu

[cknadroj]

I have the appropriate Seloc manual, but it does not cover a couple of items and only has a schematic for my motor with a generator (mine does not have a generator).<br /><br />Wiring harness from motor has four wires other than unused ones and starter motor leads:<br /><br />1- temp light circuit (brown)<br />2- solenoid circuit (white)<br />3- magneto circuit 1 to key switch (black)<br />4- magneto circuit 2 via runaway switch to key switch (black)<br /><br />From what I can tell, the key switch simply shorts the two magneto circuits together. Is that all it should do?<br /><br />Engine off, battery disconnected at the battery, motor wiring harness disconnected from the boat. When I connect my Ohm meter to the magneto circuit 1 to key switch (black) wire and to ground I get continuity (0 Ohns). Is this correct? Same for magneto circuit 2. Is this correct?<br /><br />Is the design such that because the cylinders fire at different times, one or the other black wires is always grounded so the key switch passes the ground to the other circuit to ensure the motor won’t fire when the switch is in the off position?<br /><br />Why do I ask?<br /><br />The harness was 46 years old and pretty bad shape, so I made a new one. I just want to make sure it is rewired right before I try to fire up the motor. <br /><br />Thank you.

 

[Paul Moir]

Re: Wiring - 1961 Johnson RDSL-23 40HP & 1958 LoneStar Malibu

From what I can tell, the key switch simply shorts the two magneto circuits together. Is that all it should do?

Yes, that's how it works. It shorts out the points of one magneto through the points of the other, thereby killing both halves of the ignition system.<br /><br />

Engine off, battery disconnected at the battery, motor wiring harness disconnected from the boat. When I connect my Ohm meter to the magneto circuit 1 to key switch (black) wire and to ground I get continuity (0 Ohns). Is this correct? Same for magneto circuit 2. Is this correct?

That is correct. You will sometimes measure slightly above 0 Ohms if the associated point is open. The coil resistance you then measure is around 1 - .5 ohms.<br /><br />The design works like this:<br />As the magnet passes over the igntion coil, a magnetic feild is created through the coil's iron core. This induces an electric current through the primary winding of the coil. The current flows through the point, and back into itself via ground.<br />The point is suddenly opened by the cam. This interrupts the flow through the primary of the ignition coil. This causes the magnetic feild in the iron core of the coil to suddenly collapse. This induces a moderately high voltage (but no current) in the primary coil, and a very high voltage through the many turns of the secondary winding in the ignition coil.<br />It's the secondary circuit that is fed to the spark plug.<br /><br />When you connect the two points together, the primary circuit is still being made by the point on the other ignition circuit when it's opens. So the coil never 'sees' it's point open and so the magnetic feild doesn't collapse, and you get no spark. Same thing happens to the other coil.<br /><br />There's a diagram on page 5-5, but it contains many errors. Cross out the 'Ground' just above the 'Key Switch' and write in 'To second magneto point'. Then put a connection dot on the right hand of the coil where the secondary 'jumps' the primary wire on it's way to ground.<br />Now that that's done, you can see how when you measure resistance between ground and one of the kill switch wires you'll be reading through the point if it's closed, or through the primary of the ignition coil when it's open.<br /><br />Hope this explains it! If it doesn't, post back and I'll try again.

 

[alcan]

Re: Wiring - 1961 Johnson RDSL-23 40HP & 1958 LoneStar Malibu

Good job Paul. I wish I could explain stuff that well, espiecaly electrical stuff.

 

[Paul Moir]

Re: Wiring - 1961 Johnson RDSL-23 40HP & 1958 LoneStar Malibu

Thanks alcan, that means a lot to me. I suppose it helps to have a background in electronics, and an unhealthy interest in that ignition system. <br />Oh, and thanks again for those P/Ns. I'm still not actively looking for parts for the 33hp, but a .020 over NOS piston already popped up on ebay, and I managed to snatch it up for $20.

 

[cknadroj]

Re: Wiring - 1961 Johnson RDSL-23 40HP & 1958 LoneStar Malibu

Thanks Paul - you are a master.<br /><br />My wiring does check out after all and with the corrections to the 5-5 drawing and your info I understand how the system should work.<br /><br />With any luck, I'll fire the old girl up this weekend.