Chrysler Breakerless Ignition Problem

[nipper575]

Hi all.

I've recently acquired a boat for a very reasonable sum which also came with a couple of Chrysler 75HP engines, the owner told me that neither are in running order. The older engine is in bits and has a breaker point distributor, the other which is currently on the boat has a breakerless system. The older engine has a torn seal in the bottom of the engine and the newer one supposedly had a crook CD module.

I can not get a spark to the plug. If I take the distributor out of the equation and place a plug and lead directly into the coil, when I ground the white/black wire (trigger wire, I think?) I get a spark. Does this indicate that there is something wrong with the distributor and not the CD module? I was thinking along the lines of the optical trigger unit in the distributor no longer working.

Considering I have a breaker point distributor that supposedly works, should I just swap them over or should I persevere with the breakerless unit?

Cheers.

 

[nipper575]

Re: Chrysler Breakerless Ignition Problem

Forgot to mention the model numbers of the outboards.

Breakerless ignition motor: 757HB
Breaker point motor: 757HA

I took the breakerless distributor off and replaced it with the breaker point dist. Still no spark, not sure if the CD module is compatible with the different distributor though.

One thing I did notice is if I view the IR LED on the trigger unit (of the breakerless system) through my digital camera, when 12DCV is applied I can see the LED glowing. I'm not sure whether this means it is working or not as I am not sure how to test the sensor on the other side.

Cheers.

 

[Frank Acampora]

Re: Chrysler Breakerless Ignition Problem

The CD module is the same for both ignitions. Unfortunately, the electric eye has no good test for it. Even if the bulb is glowing, that does not mean that the photo-receptor is generating a signal current.

The points should be set at .014 open on a lobe. The distributor MUST be grounded to the block because it is insulated from the mount by grease. If it is not there, run a black wire from the distributor body to the mounting screw on the mount--right where the coil grounds against it.

Take the cap off the distributor and check the center button. Also check the rotor for a mark from the button where it spins against it.

 

[nipper575]

Re: Chrysler Breakerless Ignition Problem

Thanks for the info.

The distributor body is grounded like so.



I will have to double check the points as they seemed gapped correctly (0.014 open on the lobe) to me but I need a second look/opinion as I have never set points before.

The centre button was possibly not touching the rotor, there was a very light mark on it. I stretched the spring underneath slightly to ensure that it is touching. To test it, I set the distributor so that the rotor was over the 1st cylinder post and screwed the cap back on. I then took the white/black wire off the distributor and grounded it whilst the ignition was on. I got a nice blue spark through the number 1 spark plug. I'm assuming that means that the centre button is touching the rotor now.

However, when I crank the engine with the starter motor, I do not get a spark. I also built a DVA using a schematic I found on this forum, when I measure the AC voltage off the grey wire on the coil, I get inconsistent readings. Some times I will see a flash to 150V then discharge down to 0V where it will stay whilst I am still cranking. Another crank will yield a different result, I can't get a consistent reading.

Thanks for the assistance so far.

 

[Frank Acampora]

Re: Chrysler Breakerless Ignition Problem

The distributor is grounded correctly. The blue wire, however is a 12 volt source to the elecric eye and needs to be disconnected from the terminal board on the other side of the engine or insulated at the distributor end.

Inconsistent voltage reading at the grey wire indicate that the capacitors are not charging correctly. The res wire to the CD box charges the capacitors and it should be hard wired to the terminal red post, directly to the battery. This charges capacitors at all times, whether or not the ignition is on. THUS: if the engine is left to sit for a while with the battery disconnected, the capacitors will self discharge and when the battery is re-connected you will get a spark on the wire because the capacitors are recharging. This is normal.

Check the condition of the terminal board and be certain that the red wire has excellent continuity. If all is OK, then it is likely that the CD unit itself is bad. They have a acouple of failure modes: Capacitors can short and not charge, gate transistor can short giving constant spark, internal electronics powered by blue wire can fail giving no spark at all.

 

[nipper575]

Re: Chrysler Breakerless Ignition Problem

Thanks Frank, the blue wire has been insulated at the end, that was an early pic just after swapping the distributors around. I'll double check the terminal board and the associated wires.

I'll report back with any findings.
Cheers.

 

[fcross69]

Re: Chrysler Breakerless Ignition Problem

Frank is running the preamp setup better than points I have a extra distributor laying around I may have to change over my ealry 75hp. How does it start with preamp versus points? Better or worse?

 

[nipper575]

Re: Chrysler Breakerless Ignition Problem

I managed to get it going tonight with a car coil and condenser. The points also needed cleaning. Now that I know the distributor is fine, I'm going to buy one of those MSD street fire CD units to replace the OEM unit. Hopefully I'll be able to chuck the breakerless distributor back on as it's probably fine.

Thanks for all your help, wouldn't have got it going so soon without it.

 

[nipper575]

Re: Chrysler Breakerless Ignition Problem

Thought I'd post an update.

Finally manged to get the trailer and boat registered last week so I took the boat out for a test run. It appeared to be running well at first but then it would always bog down terribly after returning to idle and then going back to WOT. Turns out I did a silly thing by not checking the timing properly. The previous owner put a new belt on the distributor drive but set it to fire at ~30 degrees BTDC at IDLE. After setting the timing so it would fire 30 degrees BTDC at WOT, it absolutely flys. Very happy with how it performs.

I have one issue that I am currently trying to fix. With all carburetors set to a touch more than 1 turn counter clockwise from fully seated, the 2nd and 3rd cylinders appear to be running leaner than the 1st cylinder after inspecting the plugs. Setting the 2nd and 3rd carb idle jets to a richer mixture buy around half a turn counter clockwise didn't seem to affect it. Whilst running at WOT, I occasionally heard a single "pop" sound which could of come from the engine. It did not disrupt the rpm of the engine whatsoever and the occurrence was few and far between. I am going to assume it was from the leaner cylinders.

I have taken the carburetors off the engine for cleaning hoping it will shed some light on the issue.

 

[nipper575]

Re: Chrysler Breakerless Ignition Problem

All back together and running well. There were traces of a black powdery substance in each of the bowls, possibly from old fuel line. Not much was found but I suppose it doesn't take much to muck things up. Also adjusted the floats in all 3 carburetors. 2nd and 3rd cylinders plugs now indicate a richer mixture so I'm happy. Put half a tank through it yesterday whilst cruising around the river, not a single pop was heard.

I'm going to replace the old fuel line shortly. Here's a brief video of it running for anyone interested.