So I fought with the regulator/rectifier going bad late last season and again early this season and the motor was running good with the CDI regulator. Then in the last couple of weeks it got hard to start and I thought I flooded it one day which was really odd because I don't do that. It was running good last Sunday and I was checking the voltage and it was charging at 14.2 volts even as I pulled up to the dock. Then on Wed last week it would not start, even trying 2 sets of spark plugs (in case I flooded it again). I tried again Thu with a fresh tank of fuel in case it was bad gas and even tried starting fluid but no sign of popping over. I checked for spark and there is none. I got towed to the ramp and pulled the boat out of the water so I could work on it at home instead of it in the water where I could drop something. I tested the kill switch circuit and that is working properly so it isn't that. I tried starting it with the regulator disconnected and no spark. The troubleshooting guides I have found make reference to wire colors that don't exist so it's tough to test some things. I'm leaning towards the cdi switch box went bad, but that can't be tested. I know it could be the stator or trigger coils or the cdm units themselves but I'm wondering if anyone has been through the no spark with a Mercury and what it ended up being. Most of what I'm reading points to the switch box and my cousin had one go bad on their Mercury a couple of years ago. The motor never had a miss so it makes me think (and hope) it isn't the stator and I put new plug wires on a couple of years ago so they are in good shape.
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MrGiggles
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You'll need a DVA adapter to do any sort of dependable testing on CDI ignitions. They are fairly inexpensive on eBay, and will work with any digital multimeter.
The high voltage DC pulses on a CDI setup oscillate too quickly for a regular multimeter to display. The DVA uses capacitors to store this voltage for a short time so you can view it. It also loads the components slightly.
Resistance tests are largely useless and really can't be relied on, unless you are getting a very obviously out of whack reading. A lot of bad parts will resistance test fine because they are not loaded or fail intermittently.
In short you need to check stator output, trigger output, and switch box output to each coil.
Same thing happened to my 84 Merc 60, stator failed which also took out the switch box. Trigger needed to be replaced as well because of rotten wires. Not a cheap weekend for sure! Prior to the all-out failure I had similar issues, motor was cranky at times, and was very difficult to start (like I flooded it) on one trip, although it eventually came around and ran okay for a couple months. All signs of a weak ignition system.
You will need to reset ignition timing as well once it's running again.
CDI used to publish troubleshooting data on a variety of outboards, it's also available in any Seloc or OEM service manual.
The high voltage DC pulses on a CDI setup oscillate too quickly for a regular multimeter to display. The DVA uses capacitors to store this voltage for a short time so you can view it. It also loads the components slightly.
Resistance tests are largely useless and really can't be relied on, unless you are getting a very obviously out of whack reading. A lot of bad parts will resistance test fine because they are not loaded or fail intermittently.
In short you need to check stator output, trigger output, and switch box output to each coil.
Same thing happened to my 84 Merc 60, stator failed which also took out the switch box. Trigger needed to be replaced as well because of rotten wires. Not a cheap weekend for sure! Prior to the all-out failure I had similar issues, motor was cranky at times, and was very difficult to start (like I flooded it) on one trip, although it eventually came around and ran okay for a couple months. All signs of a weak ignition system.
You will need to reset ignition timing as well once it's running again.
CDI used to publish troubleshooting data on a variety of outboards, it's also available in any Seloc or OEM service manual.
I tried a newer CDI switch box and still no spark. I was just checking the resistance on the stator and red to engine ground was around 105 and blue to engine ground is giving me no reading. So I think my stator is toast.
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Usually, any reading of one of the stator wires to ground indicates that lead is shorted to ground.
No reading is the right reading.
A peak reading voltmeter would be used to check stator wire to stator wire to check output of the stator to the pack or "switch box".
Very often you can visually check the wire with the reading to see if you can physically locate the location of the short. See what you can do. Flywheel should be pulled for this and will have to be pulled to change a stator.
No reading is the right reading.
A peak reading voltmeter would be used to check stator wire to stator wire to check output of the stator to the pack or "switch box".
Very often you can visually check the wire with the reading to see if you can physically locate the location of the short. See what you can do. Flywheel should be pulled for this and will have to be pulled to change a stator.
These are the specs I found (I edited it to remove year/size data I didn't need). A lot of the troubleshooting guides only show the white/green and green/white wires for the stator tests and I think that is just for the red stator. It looks like the blue to ground should be in the 3250 - 3650 range and red should be 70 - 90 with mine being a little high at 105 but that could be temperature causing a difference. I'm going to pull the flywheel anyway to take a look since it needs to be pulled to replace the stator.
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I don't know where you are reading that.
As I see it, it is wire to wire not wire to ground.
The 3250 or so reading is ohms and that is checked by connecting the two wires across an ohmeter. The ones with "V" after it are voltage output numbers. This is checked with a peak reading voltmeter and is done while the engine is cranking.
Since you apparently do not have the test equipment I would suggest you schedule a visit to a dealer with a good service dept. These checks are easy with the proper equipment.
As I see it, it is wire to wire not wire to ground.
The 3250 or so reading is ohms and that is checked by connecting the two wires across an ohmeter. The ones with "V" after it are voltage output numbers. This is checked with a peak reading voltmeter and is done while the engine is cranking.
Since you apparently do not have the test equipment I would suggest you schedule a visit to a dealer with a good service dept. These checks are easy with the proper equipment.
The column that says "Stator, wire to wire". Down in the box it shows "Blue to Eng Gnd" and "Red to Eng Gnd". Most of the other information I removed referred to specific wire to wire colors to test, but my engine shows Eng Gnd. I did pick up a dva adapter but at this point, I plan to replace most of the ignition parts since it's all 27 years old and one new piece might cause another older piece to fail in the near future.
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When you are checking stator wires to ground you are checking for a stator that is shorted to ground.
The motor is back up and running. I put in new CDI coils, a newer CDI trigger and a new CDI stator (I did the CDI ignition switch box first and a CDI regulator/rectifier earlier this year). The old coils and trigger checked out to resistance checks so I'm pretty sure it was the stator that was bad. I'm glad I decided to upgrade everything so hopefully I don't have a spark or charging issue any time soon.
I know I'm late to the party but that's normal for me.
it is not at all uncommon for electrical, specifically in this discussion, ignition components to resistance test just fine, yet they are still defective or broken.
I came from a yamaha background and one of the first things they taught us at the class in was that using resistance to test ignition components can tell you if it's good or bad or it can tell you it's good and it can still be bad. Confusing I know, but the point is, resistance alone is inconclusive. They basically told us that CDI's cannot be tested. Well they can be but there is nothing set in stone that tells us that they're bad or good, short of actually physically replacing it with a known-good unit. Stators can be the same way although "most" of the time a simple resistance test will tell if the coils of wiring are broken, shorted to one another, or just open circuit. But with that, I've personally had experiences where a pickup coil (on the stator) would test "good" yet still would not work as designed thus once again inconclusive. For those reasons I've taught myself over the years to test everything around the CDI (wiring, switches, etc) and if all that stuff tests good, either (1) try a known-good unit or just replace it. I have a big box full of CDI's that I've bought over the years that I use for testing purposes; 99% of it ATV/Side-by-Side stuff. Might have one cdi for a C55 Yamaha and maybe a stator for it but I don't remember.
As said you need the proper tools to properly diagnose. I have an old ray-pair (spell?) adapter that I use at home for personal stuff, works fine. At work we use the manufacturer-specific diagnostic stuff and in most cases we can diag a no-spark issue in under 15 minutes' time. Usually takes longer to get the dead/non-running equipment INTO the shop than it does to actually diagnose it.
it is not at all uncommon for electrical, specifically in this discussion, ignition components to resistance test just fine, yet they are still defective or broken.
I came from a yamaha background and one of the first things they taught us at the class in was that using resistance to test ignition components can tell you if it's good or bad or it can tell you it's good and it can still be bad. Confusing I know, but the point is, resistance alone is inconclusive. They basically told us that CDI's cannot be tested. Well they can be but there is nothing set in stone that tells us that they're bad or good, short of actually physically replacing it with a known-good unit. Stators can be the same way although "most" of the time a simple resistance test will tell if the coils of wiring are broken, shorted to one another, or just open circuit. But with that, I've personally had experiences where a pickup coil (on the stator) would test "good" yet still would not work as designed thus once again inconclusive. For those reasons I've taught myself over the years to test everything around the CDI (wiring, switches, etc) and if all that stuff tests good, either (1) try a known-good unit or just replace it. I have a big box full of CDI's that I've bought over the years that I use for testing purposes; 99% of it ATV/Side-by-Side stuff. Might have one cdi for a C55 Yamaha and maybe a stator for it but I don't remember.
As said you need the proper tools to properly diagnose. I have an old ray-pair (spell?) adapter that I use at home for personal stuff, works fine. At work we use the manufacturer-specific diagnostic stuff and in most cases we can diag a no-spark issue in under 15 minutes' time. Usually takes longer to get the dead/non-running equipment INTO the shop than it does to actually diagnose it.
Yeah, I was reading that the resistance testing isn't conclusive unless it tested bad and since I had already swapped out the ignition switch box and still had no spark, it left the coils, trigger or stator so I decided to replace them all vs waiting for the dva adapter to come in to do the individual testing. I still don't like the idea of mixing new components with old components so hopefully do it once and get back up and running. I did have my regulator/rectifier go bad last year so that had me leaning towards the stator acting up.
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