1991 120 hp Force/Chrysler No Spark at amy cylinder, please help.

dan2744

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I recently purchased a 1991 Maxum L-drive that had a 120 force in it. The engine was blown so i bought a 1991 120 forced outboard to swap out, but it had a different ignition system so I left it on the newly installed engine.. Everything went smooth except I cannot get it to spark at all. It was working before I installed it and I cannot seem to find the solution. I have ran jumper wires to bypass kill switch and interlock switch. It has the black and yellow wires coming from each box and I think those are just to shut the engine off. I am thinking it might be a grounding issue or something. I do have a different flywheel than what it came with and I think it is rubbing on the stator. Anybody have any idea what it could be?
 

pnwboat

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To by-pass the Kill switch, simply pull one of the wires off the switch. If you run a jumper wire across the Kill switch, that will enable the Kill switch preventing any spark. The switch should read "open" under normal running conditions. It should read "shorted" to kill the ignition.

To disable the engine kill circuit, disconnect the Black/Yellow wires from the wiring harness back by the ignition system itself.

The flywheel should not be rubbing the stator.

If you could post a picture of each of the ignition systems (original & replacement), that would be helpful in determining which specific ignition system you have, making trouble-shooting a little easier.
 

SkiDad

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most times no spark at all is the stator - you have tested the leads on that for resistance ?
 
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dan2744

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Thanks for replying, the stator test came out good. The timing is really off would that cause a no spark situation? I got it to backfire a few days ago which is funny because my kill switch was not compressed when this happened. My starter also seems to drag but does seem like its spinning fast enough to spark.
 

dan2744

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The flywheel was rubbing the stator so it makes sense if it ends up being the problem.
 

dan2744

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The stator was putting out 180 volts at the rectifier.
 

pnwboat

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The original ignition system uses a flywheel that has the six separate magnets glued to the inner circumference of the flywheel. The replacement ignition system uses a flywheel that has a single magnetic strip glued to the inner circumference. The ignition system that was on the replacement motor is the older Prestolite ignition system. The ignition system that was on the original motor is the newer Mercury Switch Box type ignition system.

If the flywheel that you are using on the replacement motor has the six separate magnets, it will not work do to the different diameters of the stators used in Prestolite and Mercury ignition systems.

You might be better off by putting the Mercury Ignition system on the replacement motor. All you have to do is to take the stator mount (with the crankshaft seal) off the old motor and put it on the replacement motor. I believe there are 5 bolts that hold the stator mount on to the top of the block. Then you can use the complete ignition system, including flywheel from the old motor.
 

dan2744

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Sadly I sold the other system. This flywheel has the one solid peace magnet. I wish I would have kept it.
 

Jiggz

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The 180 volts SHOULD NOT BE GOING INTO THE RECTIFIER. Instead it should be going to the CDM's.

The old ignition system (pics you posted) is the control box (CB) type and the new system is of the Prestolite system. That is correct, for the Prestolite system the black/yellow wire(s) are for the shut down or off. The stator wires going to the rectifier should be the yellow and yellow with black sleeve. While the stator wires that goes to the CDM's are in 2 pairs, i.e. brown/blk/yel and brown/blk/blu (these two wires connect to the CDM #1's brown/yel and brown blu wires) and the other pair is brown/yellow and brown/blu which connects to the CDM #2's brown/yel and brown/blu wires. Note both CDM's have the same colored wires for their power input from the stator but the stator wires do not.

Verify wiring is all correct. To test, for now disconnect the two black/yellow wires coming off the CDM's going to the terminal board connecting to the black/yellow wire of the cable connector. Just make sure you have some kind of manual jumper to ground these wires to shut it off, JUST IN CASE it runs!

As for that rectifier, probably needs to be replaced . . . well that is after you fix the ignition system.
 

Jiggz

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As for the stator rubbing against the flywheel, this is a big no no. If this is the case, you need to inspect and make sure the stator is the correct size for the flywheel or vice versa If not, then you can always reuse the old stator. The wiring colors maybe different but should be the same voltages and ratings. On the old stator, the two yellow wires still go to the rectifier. And for the power wires, it should be two pairs of the same color, i.e. red and red wires to one CDM and then another pair would be the red/white and red/white. Verify this by reading voltage output on each pair and should get 180VAC peak while cranking. If not then find which wire pair to which to get 180Vac peak.
 

dan2744

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The wiring is correct, mine just has the 2 green and white striped wires going to the rectifier. I will have the original flywheel on Friday and I think it might help the problem, but not sure if it will fix it. I am completely lost at this point and hope that I did not fry the CDI switch boxes but it seems weird that in mot getting at least a little spark. Its not even trying to spark, it has absolutely no spark, I just went and sanded down as many grounds as I could find and now im going to read ac voltage from stator to cdi's
 

dan2744

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My volt meter is messing up or something but it is showing voltage coming out of the stator to the cdm's, the problem is that I do not know for sure how much, I am going to have to go grab a new volt meter.
 

dan2744

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I bought new volt meter and the readings jump all over the place but each one kept saying 159 volts ac from stator to cdm's.
There is even voltage coming out of the plug wires but it jumped all over the place, now I am really lost.
 

Jiggz

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Cranking speed is actually very good. If you have voltage going into the CDM's and also getting some voltages out of the spark plug wires, have you tried spraying fuel/oil mix into the carbs just to see it is not fuel related problems. Remember, with cranking speed spark may just be barely visible at day time. Get another person to do the cranking while you are spraying the carbs with fuel oil mix. All you need is a simple spray bottle that doesn't melt with gasoliine. DO NOT USE PLAIN STARTING FLUID for if there is no fuel oil mix getting into the cylinders it could damage the rings and cylinders seriously!

If it still would not fire, remove one of the spark plugs, have someone do the cranking again while you are spraying fuel oil mix into the carb feeding the cylinder you took the plug off and watch for fuel mix to spray or mist out of the plug hole. Do this on all four cylinders just to make sure the fuel oil mix is actually getting into the cylinders. If not, then it tells you the reeds are broken. If all cylinders are misting with fuel oil mix, then spark is definitely the problem or a timing problem.

You said you are getting some voltages out of the plug wires. Is this strong enough to light up an inductive timing light. If yes, then check the timing first and then test again.

To chase the spark problem, you will need a DVA so you can properly check for voltages from the trigger, stator, CDM'S and the coils.
 
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Glastron_V210

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Hey there. Here is a link to lots of schematics for ignition systems:

http://www.maxrules.com/fixforcewiring.html

Here is one for your ig system, which is the same as mine, a prestolite cdi distriutorless 4 cyl:

http://www.maxrules.com/graphics/for...thru91A_CD.jpg

Hope it helps you to adapt it.

I built a DVA for my multimeter...it's easy if you have any soldering/electronics experience. Find info here:

http://forums.iboats.com/forum/boat-...oltage-adapter


Troubleshooting guide here: (I had to break up the address for some reason...just eliminate the spaces)

http://www. jm sonl ine.net/articles/cdi-ignition-trouble-shooting-guide-for-chrysler-force.htm

Perhaps this website has a block on that website. Anyway, the info is good, I used it to determine a loose connection.

In particular, I'd start with the CDI stator pairs. As you will note on the schematic, the battery charge stator winding is seperate from the two CDI ignition power supply windings. As such, measuring the green wires for voltage will not yeild usefull information.


Please start with the DVA voltage readings (Or use a 'scope if you have one) of the stator power supply windings.


Chay
 
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dan2744

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The timing is way off for sure, will this cause no spark, can I time it without it running?
 

dan2744

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Thanks for the help guys! I did spray mix in cylinder 1 and still no spark, I thought it was getting fuel but it might not be, when I installed the reeds I just put them in. Do they go in a certain way? They looked fine and looked like they only go in one way but didn't find any info about how they actually are supposed to be installed. I have tried 2 different sets of plugs but I suppose I maybe did not see spark because it was really bright and sunny out today.
 
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