Chrysler 1981 55HP Possible CD problem

[Joe22]

I have a sparking issue with my 559H1N. I've gone through the whole process of rebuild carb, resetting carb link, idle screws, throttle link etc and even re-did the timing on it as per Frank's video, previous owner liked to touch things I'm guessing. Now I've finally got it firing up and I've got spark on both cylinders but once the motor warms up, say after 1 minute, I lose spark in #1 cylinder. I try to check the timing to see where it's sitting but my timing light doesn't show anything. So I test the spark plug and no spark. Need help please

 

[Nordin]

I suppose you have the Prestolite CDI ignition system with trigger ring, CD box and two ignition coils.
First try to swap the coils and see if the issue follows the swap.
If the #2 cylinder loose spark the issue is the ignition coil.
If not check the connectors for the trigger signals, the connectors for the ignition coils and the connector for the stator.
To troubleshoot the system you have to have a DVA adapter to measure the peak voltage from the trigger, stator and the CDI box.
Outboardignitiondotcom has the troubleshoot chart and spec chart for the components.

Output voltage from the CDI box to the coils should be 200VDC or higher.
Trigger voltage from the trigger ring to the CDI box should be 0,5VDC or higher.
Stator output to the CDI box should be 180VDC or higher.

 

[Joe22]

That is correct. Tried that and it's not the coils.
Ok I'll have to try and source one of them and see someone who has an adapter.
Any idea why it only does it when it's hot and not cold? I've tried looking for damage to the wires but can't find anything

 

[Nordin]

Maybe there are some electronic components or one component in the trigger ring or in the CDI box that will fail while it is getting warm/hot.
As you have spark at one coil I think you can exclude the stator.
If the stator fail you would not have any spark at all.
If you are a little handy and can handle a soldering iron you can build your own DVA adapter.
It contains a diod, resistor and a capacitor and the purpose of it is to charge the capacitor with the peak voltage soo you are able to see the value of the peak voltage as the capacitor does not discharge so fast.
Google DVA adapter and there will show up a lot of diagrams.
The problem is to troubleshoot when it starts to fail.
You have to have the tools with you when you are out at the lake or are you able to force the fail having the engine at the driveway?

 

[Joe22]

It fails in the driveway, that's how I picked it up. Was getting it ready for the water so was double checking the timing and that's how I noticed it as the timing light wouldn't show the markings as it warmed up. It's been having trouble idling so that's why I was going through the process of cleaning and resetting everything.

 

[jerryjerry05]

You said: Was getting it ready for the water so was double checking the timing and that's how I noticed it as the timing light wouldn't show the markings as it warmed up.
The Force/Chrysler timing marks: the timing is set at wide open throttle and not running. If you get it running and search for the marks, they'll be around the flywheel, just not at the timing mark.

 

[Joe22]

Ok thanks Jerry. So just to be clear, they will only be seen at the motor mark at cranking with the spark plugs grounded or WOT? Could be the reason why I couldn't see them but it also helped me realise the top cylinder wasn't sparking properly. Now I have doubts about it all, will have to test it again tonight and see results.

 

[Nordin]

Joe you would see the timing mark at idle and should be about 3dgr BTDC at about 800-1000 rpm.
Timing decal is for top cylinder and you can make an own mark for bottom cylinder. Should be 180 dgr from top cylinder.

 

[Joe22]

I've gone through the testing and I'm only getting 0.05 volts from the trigger. Is there anything I can do to fix this or do I need a new one?

 

[Nordin]

Spark at one cylinder but only 0,05V from both triggers?
If you got only 0,05V from both triggers you should not get any spark at all at both cylinders.
0,05V from the faulty cylinders trigger, yes you have a bad trigger there.

 

[Joe22]

Yeah for some reason I'm not getting any spark now so looks like I need to search for a new one

 

[Joe22]

Ok seems like problems solved.... then I took a breathe. Had spark in both cylinders, went to go set the timing and it seems the timing is now 180 degrees from my motor mark. All wiring is the same, nothing has been swapped over and took photos before and after to make sure plus all the plugs only clip in 1 way. I'm now getting intermittent spark in #1 cylinder again. Crazy question, could this all be battery related (purchased new) or what should I be looking for?

 

[Nordin]

This is a self generating magneto CDI system soo battery would not affect the timing. Only if the starter turn to slow soo the magneto do not produce enough power.
Battery only for the starter and aux.
The stator has windings, one charging the CD box (blue and yellow wires) and one for the battery charging (green/yellow wires).
If the timing is 180 dgr off the trigger wires are swapped.
Timing mark at the flywheel is for top cylinder.

 

[Joe22]

Hence my problem, it can only be connected one way and the flywheel has never been taken off (well not since I've had it). The other photo is where the timing light now shows 30BTDC at WOT instead of the motor mark where it was showing last week which is 180 degrees from spark plug (and have rechecked with a screwdriver). Could the CDi be causing this? I'm trying to make sure I know the exact problem as postage alone from USA will cost me a fortune.

 

[Nordin]

But if you can not connect the prime side of the ignition coil wrong cause the connectors only goes one way there are ignition coils dedicated for cylinder one and cylinder two.
You are not able to switch the ignition coils.
I believe you can swap the coils, that is what I remember.
But it was more then 6-7 years I worked with this ignition systems for the twin carb 55-65Hp Chryslers soo I do not remember exactly.
If the top cylinder spark at 180 dgr at idle the bottom would spark at 0 dgr.
Is the bottom sparking at 0 drg?
Swap the HT wires ????
If the top now sparking at 180 dgr you would not be able to start the engine.
Check the wiring with the diagram for 82-85 55Hp Chrysler which you can see at Mastertech marines web site.

 

[Joe22]

It's all correct by the diagram except it doesn't say which one is the orange or red coming from the cd unit. The picture I have is from the original manual and that's how I have it wired. Will try swapping them over tomorrow and see if it does make a difference.

 

[Nordin]

My OEM service manual Force 35 and 50 Hp calls for orange top cylinder and red for bottom cylinder.
The 50 Hp Force has the same ignition system as your 55Hp Chrysler.

 

[Joe22]

Orange is number #1, red number #2. Ok so I've grounded the spark plugs, hooked up the timing light, turned the motor over, I have spark on both cylinders and the timing is at the motor mark at roughly 0TDC. I engage the kill switch in on the gear selector and go to WOT and it all changes. I then lose spark at cylinder #1 and the timing goes 180 degrees. Surely that can only point to the CDi unit? This is driving me crazy now. Is there any other options before I spend a fortune on a new CDI or could it be the kill switch? Can I join the 2 wires and bypass it or is that not an option?

 

[Joe22]

Update.... I've bypassed the kill switch and same problem occurs. It has to be the CDI somehow changing the ignition pattern?

 

[Nordin]

Well, I have no more information to add now.
I think you have to change parts by now as it sparks and suddenly change the firing order.
There are used CDI boxes at Ebay, but better to buy a new OEM or an aftermarket by CDI Electronics.
CDI Electronics part number 116-5301, but really expensive.
About 400 dollars ...... uuuuuh.