1977 Chrysler 90hp: No spark

[mculpii]

Before I go an order a new CDI unit I wanted to double check my findings. Initial problem with the boat while at the lake it would be running fine then start dying. It wouldn't sputter or anything it would just slowly go back idle and if I didn't pull throttle back to idle it would die. It was almost like it was running out of fuel. This progressively got worse. Last lake trip it never restarted on lake and has not started since.

Initial findings:
1. I have no voltage on the grey wire on the positive post of the coil, key on, all wires connected (I'm not sure that I'm testing this correctly per the article from http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=2&ved=0CHEQFjAB&url=http%3A%2F%2Fwww.cdielectronics.com%2FTechService%2FDVA%2520Explained.pdf&ei=N3oUUKKyLY-E8QSJtICgBw&usg=AFQjCNHs9YoujO_P3ZVxRsorbCVaNxN7-w as I'm not using a DVA adapter and have not tested for AC voltage)
2. When disconnected and key on I get a steady 6.xx volts DC on the grey wire
3. My trigger wire on the distributor does fluctuate my digital fluke meter
4. My light blue wire has 12.xx volts at the distributor
5. The ground wire from the CDI box when disconnected from the coil gives .2 ohms when I tough the opposite lead to the distributor ground
6. The back of the CDI unit filler material used to insulate the electronics is soft and appears to have melted downward.


Other items:
1. This has a magna power electric ignition
2. I assume based on my reading that this is a battery CDI setup and not a magna power2, as none of the troubleshooting directions for the magna power2 seem to apply.
3. I have not disconnected the trigger lead from the distributor and done the touch to ground test as I don't believe if I have enough voltage going to the coil it makes a difference.
4. I recently installed this motor and did the wiring hook up myself. We went from a Force 90hp to this motor. I had a boat shop install the motor. I used one of my tilt trim wires to power the blue CDI wire and I have it jumpered underneat the dash to switch power on key. We had a few successful lake trips and have 3 hours on this motor.
5. Maybe this is for a seperate topic but the 2 wires that come from the old magneto are just cut off and don't connect to anything. I believe I don't have any charging of my battery happening because these don't have an alternator or generator, correct? yes, my battery voltage stayed well over 11.5 volts during lake trips and is currently charged completely.

I'm just looking for some feedback before I buy a CDI setup.

 

[Frank Acampora]

Re: 1977 Chrysler 90hp: No spark

Chrysler used the term "Magna Power quite loosely. What you have is a Motorola Magna Power ignition.And yes, the CD box is not functioning based on your remarks. The grey wire to the coil should have pulsing voltage as you turn the flywheel and the distributor signals the box to dump the capacitors into the coil.--one pulse for each cylinder as it fires. Steady voltage means that the internal switching transistor has failed. Unfortunately, these aluminum CD boxes are potted and you need to destroy the internals to repair them. Thus, it costs as much or more to repair as to buy new. If you turn the flywheel by hand with the plugs out and ignition on, you may see a steady spark --bzzzzzzzzzzzt--at the firing point of each plug instead of a single "snap"

Magna Power II has all components except the individual coils under the flywheel and no distributor.

Up under the flywheel on your engine is a 12 pole stator which supplies about 16 volts A/C current which then is modified by a regulator/rectifier to charge the battery (and power the ignition). If the two wires are cut, then you are not charging the battery. If they are long enough, you can repair them but it would be better to use a stator off a junker engine. Since the ignition uses power from the battery, eventually it will discharge below the level of reliable ignition, so, make repairing the alternator a priority task.

 

[mculpii]

Re: 1977 Chrysler 90hp: No spark

Frank,
Thank you for replying to my post. I ordered a CDI box and coil and will keep you posted.
Thanks

 

[mculpii]

Re: 1977 Chrysler 90hp: No spark

Frank, does the stator simply hook up to the regulator/rectifier? I need to try and hook this up to see if it will charge. It has 1 ohms on it. I recall 3 posts on that regulator which I believe has a purple wire and a red wire. Do I use those posts or the third one as well. Any insight would be great. By the way the boat has been running great. That CDI made all the difference.

 

[Frank Acampora]

Re: 1977 Chrysler 90hp: No spark

The 12 pole alternator stator has relatively heavy gauge windings and will not show a high ohms reading. As long as it does not show infinite, it will probably deliver A/C voltage. However, understand that these old engines were not used on boats with a lot of electronics. The alternator will supply about 6 amps, enough to run the CD ignition and recharge the battery, but not much more.

Looking at the regulator, the two left posts are connected to the alternator stator wires. The purple wire usually connects to the center post but it also is usually not used and you can leave it unattached. It is sometimes used for a tachometer signal.

The post on the right is the positive DC output and the red wire connects to it. Follow this red wire to the terminal board and you will see another red connected that travels to the circuit breaker. A separate red from the circuit breaker connects to the battery side of the solenoid. This is how the battery is charged and the electrics are protected.

Back to the terminal board, a red wire from the CD box is connected. This powers the capacitors and is always on whether or not the key is on. That is why if you disconnect the battery and leave it set for a couple of days, when you reconnect, you will get a spark at the battery terminal.

A black ground wire connects the side post on the regulator to one of the starter mounting nuts.

 

[mculpii]

Re: 1977 Chrysler 90hp: No spark

Thank you, I successfully hooked it up and am getting 13 volts. Way cool. Beats a discharging battery. The other plus is my purple wire now runs my tach correctly. Great stuff. My new CDI box doesn't have the old output. Thanks Mitch