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84 Chrysler Star 90 HP Dead in the Water and out

D

Dave Spoula

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"Open to all. I'm lost on

"Open to all. I'm lost on this and need some help. Although I'm pretty good with Chrysler RB engines (440/383 cu automotive), I'm now at a loss on my 1984 Chrysler 90 HP, 4 cyl. outboard.

First, so you know what we're working with here .....
1984 Chrysler (Star) 90 HP 4 cylinder
Model # 906S4A (nine-zero-six-ess-four-a)
Serial #1036 (one-zero-three-six)
Operating Range 4250 - 5250
BIA HP 90 at 4750

I believe the ignition system is the "Prestolite Magnapower III" (Type III Ignition System per Seloc Chrysler Outboard Repair Manual 1962-1984, copyright 1988, page A-52 in the Appendix). I also believe this is referred to as the "Alternator/CD" ignition.
I am troubleshooting based on the above named Seloc Repair Manual.
I am limited to an Analog VOM for testing purposes.

Symptoms .....
Engine will not start.
Ignition switch checks fine. Also tried a replacement with no improvement.
I have spark on only cyl. #3. The spark is good.
Swapping the other 3 coils into the #3 position, all produce a good spark.
Swapping the CD units still produces spark on cyl. #3 only.
Stator windings visually from bottom side, ( I have not pulled flywheel as yet), appear to be OK and is producing voltage across the blue and yellow leads to the CD units.
The triggers indicate continuity and no shorts to ground.


I'm interested in direction for the correct Chrysler Service Manual, troubleshooting recommendations, parts recommendations and reputable suppliers.
Can you help me out here?
TIA,
Dave Spoula
[email protected]"
 
"Dave,

The ignition system

"Dave,

The ignition system that you have is identical to the Force engines of the late eighties and early nineties. Chrysler became Force in the mid eighties, and Force was later bought by Quicksilver (Mercury).

Generally, when replacing ignition components for these engines, you have to go with rebuilt units. Even if you order direct from Quicksilver, you will get rebuilt units for many of these engines. "Rapair" is the name of the company that rebuilds electronics for many engines, and I am most familiar with their products, although there are other companies that do this type of work.

Often, the rebuilt units are a bit different from the originals, and in many cases are redesigned to perform better and more reliably. In some cases you have to replace components in groups because the new parts will not work with the older style parts. Generally, it is best to replace the entire ignition system at once, because malfunctioning components often cause damage to other components.

Before you decide to replace everything, I would advise you to pull the flywheel and examine the two magnets in the hub which activate the trigger coil. If these are cracked the trigger will not function properly. Based on what you said, I think the problem has something to do with the trigger, but these ignitons systems are very tricky because of the way they are designed so I would hesitate to say the the trigger is definitely the problem. I believe that the trigger coils ground through the CD units, so this complicates matters quite a bit.

You can troubleshoot these ignitions with a ordinary voltmeter, but I find that a meter with a needle is more useful that a digital meter, especially when testing the trigger. You can detect the pulse from the trigger by watching the needle, but the digital meter will not give you a reading that you can feel confident with. If you see the needle jump with regularity you can be pretty sure the trigger is working, but remember to check if the trigger is grounding.

The stator leads should generate A/C voltage. I will see if I can give you some numbers for the output later today. I will have to look through some of the material I have on these motors.

"
 
"Hi Tonyob,
Thanks for you

"Hi Tonyob,
Thanks for your response. I do have the analog type (with needle). Are you indicating I should be seeing the needle swing when cranking the engine from the trigger leads? Seloc Manual is a bit vague to me.
I also believe there is a print error or something is missing in the in Seloc Manual. In the topic of "Trigger Coil Test", it has me checking continuity (which is good across all four) then it goes into "If the CD module fails both tests, remove the unit and take it to your local dealer .....", all under the "Trigger Coil Test" heading.
Also, can you direct me to where I might obtain a copy of the Chrysler Service Manual for this engine? Seloc Manual is Ok I guess but I'd rather have the real manual for this.
Thanks again,
Dave Spoula
[email protected]"
 
"Dave,

You should see the n

"Dave,

You should see the needle move when cranking if you touch the test leads to the trigger coil wires. Choose milliamps or the lowest amp setting you have. Try the lowest voltage setting you have also. If you can't get the needle to move at all you have a bad trigger coil. Test the trigger while all wires and plugs are connected.


All of the manuals are a bit vague about testing the ignition system.

Try the troubleshooting pages at www.outboardparts.com. You will find as much information there as any other source.

I think you can find a service manual here at Marine Engine, maybe Andrew can direct you to it.

What reading do you get at the stator leads? I could not find any specs for output on the stator.

"
 
"Tonyob,
Thanks again for

"Tonyob,
Thanks again for your input and time on this.

I only had a hundred other things to do today so I went ahead made it a "boat day" and pulled the flywheel off. Wife's not to happy about that but oh well.

No broken magnets and no visible cracks turned up on the flywheel. Both magnets, inner set for the triggers and outer for the stator, appear to have good "pull" to them. Nothing appears to have been rubbing another surface.

The stator looks ok I guess with no evidence of burning or smell of burnt plastic. There is some gray color to toward the ring but the windings themselves are visible through the plastic. Also, the triggers appear intact and clean.

Before I pulled it apart I checked stator output at cranking speed with a DVM and came up with 196.8 VAC on one side and 197.4 VAC off the other. There were no shorts to ground from any of the four leads.

I also checked trigger resistances and voltage at cranking speed. All four range from 49.1 ohms to 50.6 ohms. Again, no shorts to ground from any of the eight leads. I could only get .05 VAC across the four sets of trigger leads. Seems low to me.

All the above readings were taken with the quick disconnects apart one at a time. I see you're suggesting to leave them intact. Might I see a difference when connected and testing?

I found the literature page on this site for service manuals. They do not list my model engine but the order was accepted. Have not got an Order Verification as yet so I'm wondering if it went through.

Thanks again,
Dave
[email protected]"
 
"Dave,

It sounds like the s

"Dave,

It sounds like the stator and trigger are okay to me.

Tony"
 
"Tony,
Sorry to go back ov

"Tony,
Sorry to go back over this but is the .05 VAC (at cranking speed) from the triggers enough to make the CD units fire?

If so, would you reccommend just replacing the two CD units?

Thanks again,
Dave
[email protected]"
 
" Dave,

The reading that yo

" Dave,

The reading that you are getting is not a true reading. You would need a peak reading voltmeter for an accurate reading on the trigger coils. The fact that you are getting a reading at all leads me to believe that the trigger coils are working.

On the other hand, when you find spark in only one cylinder, even after swapping the CD units and coils, it points to the trigger. I have been stumped by problems like this in the past and I have all of the recommended testing equipment. I recall two engines that had similar symptons. Everything tested fine according to the gauges and specifications. I resorted to simply replacing components. One engine needed a trigger, the other needed a stator.

Tony "
 
" Tony,
I know this probl

" Tony,
I know this problem is from last year but I felt an update may be useful to others that read.
I finally took the $$ plunge, purchased 2 CD units and a starter solenoid. Turns out that is what it needed. Without any other changes, I set up a home-made spark tester, plugged everything in, and had fire on all four. Took it down to the river and found it to have much more power than I can remember before it died.
Thanks again for your time and wisdom. This year will be a bit more plesant now that we're boating again.
DS "
 
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