Ok, I will give a great deal of detail here in hopes of pre answering any questions.
I am a very experienced electrical technician, so don't hesitate to provide detailed technical advice.
Motor Info
2001 Mercury 25EL
2 stroke
Issue
No Spark
Tests, Results, and Remedies
I purchased the repair manual online here. And I purchased a DVA for my fluke.
Prior to purchasing the manual, I was limited to testing without knowing what readings were acceptable. Because of that, I had concerns about the coils and the rectifier. I also didn't know exactly what I should see on the switch box either. In an attempt to just skirt all the searching and re testing, I purchased all 4 items new.
2 new coils (which test almost exactly the same as the old ones) but I sill installed the new.
A new rectifier (which also tested the same as the old one) and I still installed it as well.
New Switch box which I didn't test either with a meter because even checking resistance across wires might apply small amounts of voltage and I did not want to damage any circuitry.
So, with all the new components, I got the manual and started checking every component.
All 4 coils were 1 ohm or less on the primary
and around 10K ohms on the secondary
The plug wires were both around 1 ohm
The trigger was around 7.5K ohm
Here is where I am really struggling to figure out what the hell is going on.
The Stators
According to the manual I can ohm across the leads on either the charging stator or the ignition stator. I did and both seem well within acceptable levels. The manual however on the chart calls the green leads the "Charge Coil" but I am assuming that's because it provides the charge to the coils. Either way, the green leads have a specific instruction on the manual chart.
It tells me to ohm across the leads and look for 370-445 ohms. I was right around 390….. Perfect
Then it tells me to check each lead to ground one at a time using the DVA for voltage when cranking. It tells me the voltage should be between 150-330. Now….. first question there is it does not state whether this is AC or DC voltage. Clearly since one stator goes to a rectifier and then to the battery, that tells me there is AC voltage coming off that stator and being rectified to DC for charging the battery while running.
But on the coil stator, I was not getting detectable voltage on either AC or DC when reading from either lead to ground.
With that issue kicking me in the nuts, I ordered another stator. Directly out of the box it read 400 ohms lead to lead. Right in line with the other stator. I installed the stator and checked voltage when cranking again lead to ground on each green lead. Once again I had nothing.
The manual is very clear with an Asterisk and note saying
"Check stator output voltage between each wire and ground (meaning G/W and ground, then W/G and ground) NOT across the two stator wires like the resistance test. "
After the new stator tested exactly the same as the old one…… I began to throw a temper tantrum LOL
I decided to check voltage across the leads just for the hell of it.
When I turned the key over, the DC voltage across the leads with a DVA was 170 volts. HMMMMMMMMMM with is going on.
So I put the old stator back on and checked it the same way. Same as the new one, the old stator was 163VDC
Not that the starter circuit really matters, but just due to it kind of not wanting to turn over a month ago, I replaced the starter, the start solenoid, removed and tested the neutral safety switch and the kill switch. All of which tested as expected. Both showed open and closed contacts in their open and closed state.
I have been losing sleep at night thinking about what I should have tested, or thinking, "Did I test that on DC or AC, Did I test that to ground or across" Etc Etc. Every day for a couple weeks now I have waited for parts to come in thinking I had it solved, tested and re tested to no success.
Additional note…….. I have not only installed new spark plugs, but I have now also tested the output of the switch box at the coils.
According to the manual I should have 125-300 volts (and of course it does not specify AC or DC so I have tested on both using DVA and without DVA)
At the coils, the longer I hold the key the more it climbs. But it takes 15 or so seconds to reach 3 VDC.
This is the same with the old switch box and the brand new on also.
So……….. who can tell me what obvious thing I missed or what completely strange thing I should check. I'm ready to use the motor as target practice, but I was trying to sell this boat and it ran fine one day, and a few weeks later I wanted to put it on the trailer to clean it up to sell and I have been pulling my hair out ever since.
I am a very experienced electrical technician, so don't hesitate to provide detailed technical advice.
Motor Info
2001 Mercury 25EL
2 stroke
Issue
No Spark
Tests, Results, and Remedies
I purchased the repair manual online here. And I purchased a DVA for my fluke.
Prior to purchasing the manual, I was limited to testing without knowing what readings were acceptable. Because of that, I had concerns about the coils and the rectifier. I also didn't know exactly what I should see on the switch box either. In an attempt to just skirt all the searching and re testing, I purchased all 4 items new.
2 new coils (which test almost exactly the same as the old ones) but I sill installed the new.
A new rectifier (which also tested the same as the old one) and I still installed it as well.
New Switch box which I didn't test either with a meter because even checking resistance across wires might apply small amounts of voltage and I did not want to damage any circuitry.
So, with all the new components, I got the manual and started checking every component.
All 4 coils were 1 ohm or less on the primary
and around 10K ohms on the secondary
The plug wires were both around 1 ohm
The trigger was around 7.5K ohm
Here is where I am really struggling to figure out what the hell is going on.
The Stators
According to the manual I can ohm across the leads on either the charging stator or the ignition stator. I did and both seem well within acceptable levels. The manual however on the chart calls the green leads the "Charge Coil" but I am assuming that's because it provides the charge to the coils. Either way, the green leads have a specific instruction on the manual chart.
It tells me to ohm across the leads and look for 370-445 ohms. I was right around 390….. Perfect
Then it tells me to check each lead to ground one at a time using the DVA for voltage when cranking. It tells me the voltage should be between 150-330. Now….. first question there is it does not state whether this is AC or DC voltage. Clearly since one stator goes to a rectifier and then to the battery, that tells me there is AC voltage coming off that stator and being rectified to DC for charging the battery while running.
But on the coil stator, I was not getting detectable voltage on either AC or DC when reading from either lead to ground.
With that issue kicking me in the nuts, I ordered another stator. Directly out of the box it read 400 ohms lead to lead. Right in line with the other stator. I installed the stator and checked voltage when cranking again lead to ground on each green lead. Once again I had nothing.
The manual is very clear with an Asterisk and note saying
"Check stator output voltage between each wire and ground (meaning G/W and ground, then W/G and ground) NOT across the two stator wires like the resistance test. "
After the new stator tested exactly the same as the old one…… I began to throw a temper tantrum LOL
I decided to check voltage across the leads just for the hell of it.
When I turned the key over, the DC voltage across the leads with a DVA was 170 volts. HMMMMMMMMMM with is going on.
So I put the old stator back on and checked it the same way. Same as the new one, the old stator was 163VDC
Not that the starter circuit really matters, but just due to it kind of not wanting to turn over a month ago, I replaced the starter, the start solenoid, removed and tested the neutral safety switch and the kill switch. All of which tested as expected. Both showed open and closed contacts in their open and closed state.
I have been losing sleep at night thinking about what I should have tested, or thinking, "Did I test that on DC or AC, Did I test that to ground or across" Etc Etc. Every day for a couple weeks now I have waited for parts to come in thinking I had it solved, tested and re tested to no success.
Additional note…….. I have not only installed new spark plugs, but I have now also tested the output of the switch box at the coils.
According to the manual I should have 125-300 volts (and of course it does not specify AC or DC so I have tested on both using DVA and without DVA)
At the coils, the longer I hold the key the more it climbs. But it takes 15 or so seconds to reach 3 VDC.
This is the same with the old switch box and the brand new on also.
So……….. who can tell me what obvious thing I missed or what completely strange thing I should check. I'm ready to use the motor as target practice, but I was trying to sell this boat and it ran fine one day, and a few weeks later I wanted to put it on the trailer to clean it up to sell and I have been pulling my hair out ever since.
