73 55hpChrysler magneto ign to 85 force electric ign swap issues

[tater76]

Ok folks, I have a 1973 55hp Chrysler and a 1985 50HP Force. The Force is blown, but has good ign parts. I swapped all the Force ign to my Chrysler, and now it won't turn over at all. I removed and replaced the Force ignition exactly as it came originally. Everything fit perfectly, and it was an easy swap. I took before and after pics for reference, and everything is exactly where it should be. When I turn the key nothing happens? I don't have a multi meter to check voltage or continuity, so does anyone have any advice? Could the rectifier be the cause of not even turning over? I am familiar with old motors, so this newer ign style is greek to me. Any help would be great. Oh, and I did check the wiring diagrams, and everything is placed correctly.

 

[jerryjerry05]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

That shouldn't be a problem with the starter not turning.Profile,you might be close to someone who can help.
Test light?Check the lugs on the solenoid.Have someone try the key as you touch the lugs.
When the key is turned you should see power at the yellow/red wire and the lug going to the starter.Check the connection strip.Then check the key switch.Your choke work?J

 

[steveclv]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

The ignition system is very easy but your problem at this stage has nothing to do with the ignition - it's the starting circuit.

Step 1. Take a length of wire directly from the battery + to the yellow wire on the starter solenoid. The solenoid should click and the motor should try and start so watch your fingers. If it doesn't then check the neg/ground wire between the motor and the battery. Check/replace the solenoid.

Step 2. Assuming that the motor would spin then check the interlock microswitch - this is what stops the motor from starting in-gear - maybe you dislodged it. Bypass the terminals with a piece of wire and see if the motor will spin. If it does then adjust the switch so that it 'makes' when the throttle lever is in neutral.

Get the motor spinning and then you can test the ignition system

Just a final thought - the battery is fully charged isn't it

 

[tater76]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

Hey thanks for the quick response guys, so I tried everything that was suggested but no juice at the yellow wire on the coil in any circumstance. I swapped coils, tried nearly everything in my knowledge to get juice to the motor. So, I am thinking that it may be the ignition "key switch" I picked a new one up today and will install it then let you know. A question though, and pardon my lack of wiring knowledge, but if the battery pos + lead goes to the left hand side of the solenoid, and the pos + lead on the right goes to the starter, all that is left is the yellow ignition wire that actuates the solenoid to open the circuit? I am just not getting the solenoid to open up the circuit. I tried a jumper wire on the neutral switch, tried jumping yellow to battery, and nothing happened. I am just trying to think how the yellow wire gets energized to let the solenoid do its job?

 

[Frank Acampora]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

Just take a big screwdriver and short between the yellow terminal and the battery side of the solenoid. If nothing happens, then the solenoid is bad, OR the ground side is not connected. On those solenoids there are usually two small terminals. Yellow goes to one and a black ground comes from the other to a good engine ground. If there is only one small terminal, the ground is through the frame of the solenoid, but this is old style and you should not have it.

To answer your question: Red (power) comes from the engine terminal board to the ignition switch. yellow goes from the ignition switch to one side of the neutral interlock switch. Yellow comes from the other side of the neutral interlock switch to the small terminal on the solenoid.

When you turn the ignition switch to start, and the engine is in neutral, power will flow from the red "B" terminal to the yellow "S" terminal. It then goes to the interlock switch and if the white button is depressed, power flows to the yellow terminal on the solenoid and out to ground. This energises a small elecromagnet inside the solenoid that closes the heavy duty high current contacts between the two large terminals. Power flows to the starter.

 

[tater76]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

Thankyou Frank, that is exactly what I tought. However, I have tried two different solenoids with the same result. I checked the ground it is good, but there is a small black "I think" ground wire coming from the same loom as the choke and yellow ignition wire. My initial thought is to ground it to the motor? I can and have turned the motor over by jumping the two solenoid points together, and it turns beautifully, just no spark. Should I replace the ignition switch on the dash? it feels wierd when you turn it?

 

[Frank Acampora]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

Oops! I was thinking you had an 85, not a 73---Chalk it up to Alzh--alzh--so anyway i went to the movies--wait! Who are you? Who am I?

Back to the present: If you have the old style solenoid with only one terminal, it is not mounted on rubber isolators (I think--been a long time since I used one of them) and grounded through the mount and engine pan. The pan is NOT a good consistant ground as it is not attached directly to the block. Older models did have a short length of heavy ground wire running from the bypass cover to the pan. Anyway: The black wire should have a 1/4 inch ring terminal and must be attached under the head of one of the solenoid mounting bolts for a good solid ground. If you ARE using a two terminal solenoid, attach it opposite the yellow wire.

If that doesn't work and your switch feels "funny" then short from red to yellow at the switch. If it cranks now, the switch is indeed bad.

 

[tater76]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

Thanks for all the help guys, so grounding the solenoid was in fact the issue. It turns with the key now, but I have no spark I checked to see if the coils were getting juice when the key is in the on position and they are not. They should be energized when you turn the key right? Also, the yellow lead on the solenoid gets no juice whith the key on either, should it? I am beginning to think that the key switch is wired differently for the two different typs of ignition? It looks identical to what the manual shows, so...?

 

[tater76]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

Here are some pics of what I am dealing with.

 

[Frank Acampora]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

The ignition switch is indeed wired differently for magneto and battery ignition. The yellow wire is attached to the "S" terminal and only gets power when you turn the key all the way to start. So, with the key in the "on" or "run" position, it is correct for it to not be powered.

NOW: For MAGNETO ignition, the blue and white wires are the stop circuit and are attached to the "M" terminals.

For BATTERY ignition, the BLUE wire supplies power to the coils and MUST be wired to the "I" terminal. "I" terminal is energised in start and run positions of the key. So if the engine stalls for whatever reason and you decide to sit at rest for a while, turn off the key or you will drain the battery.

White (at the switch) is no longer used. No harm will come from leaving it attached to one "M" terminal. It is now signal for a tachometer. Note that it is not the other white wires at the engine.

Blue supplies constant power to both coils. With the points closed, voltage flows through the primaries of both coils to ground. When the points open, the ground is lost, power is stopped and the magnetic field in that respective coil collapses, inducing a high voltage to jump the plug gap.

 

[tater76]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

That makes perfect sense, thanks Frank I am going to go rewire the switch right now

 

[tater76]

Re: 73 55hpChrysler magneto ign to 85 force electric ign swap issues

She lives!!! So the OMC key switch did not have an I terminal and was pretty worn, so I went to my neighborhood NAPA and bought something close. I plugged it in and very first turn she fired and began to idle smoothly What a feeling! after a few weeks of the rebuilding process, some snags, and some good advice it runs better than when I bought it! Thanks to all for the advice