I’m calling this my one thing after another Husqvarna post

bertsmobile1

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  • / I’m calling this my one thing after another Husqvarna post
OK
First of all you are doing things the wrong way round.
You ask here first , get told the truth then go on You tube to try and find some one who knows what they are talking about ( cuts out about 75% of them ) then watch how they do it .
If the coil has a remote control unit ( often called an exciter ) then you can test it with an Ω meter and the engine manual will list the limits .
If the coil has an embedded Hall Effect trigger chip in it then it becomes a "Module" and it can not be tested with an Ω meter other than a secondary reading on the HT side .

Now fools skim through a manual and see some numbers then they decide that the numbers for a specific engine must be the same for all engines and publish total BS on You Tube .
Once upon a time I tried to correct some of them but that always results in me being abused, flamed & trolled by the presenters loyal disciples who will not tolerate any criticism of their messiah .

To test a module you need an oscilloscope plus the appropriate signal generators and even a flux generator, thousands of dollars worth of gear to test a $ 40 part .
Now the output of a module gets tested with a variable gap meter
B & S make a simple 2 gap one which gives you a pass / fail result or you can get any one of a number that have a moving contact that can be moved further apart till the spark can no longer jump the gap.
However to be of any meaning full value you need to know things like the number of turns on each winding within the coils the strength of the ignition magnet, the air gap between the coil & magnet the air pressure & humidity in your workshop , your altitude etc etc etc .
So in reality a good / bad test is quite enough
The resistance of AIR at 150 psi over a 0.030" gap is roughly equivalent to the resistance of AIR over a 0.50" gap at sea level .
This is how those old Champion plug testers worked
They had a trembler coil in them that produced a consistent stream of sparks and you increased the air pressure around the spark plug till the spark stopped jumping the plug gap .
A great toy for convincing a car owner that perfectly good spark plugs needed to be replaced

And a word of warning about using those sliding contact spark testers
If you are still generating pulses from the engine and the resistance at the testers gap is too great for the electricity to jump then YOU can become the conductive path OUCH or even RIP so you only widen the gap to .05" or till the spark stops whichever happens first .
 

Douglasdzaster

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  • / I’m calling this my one thing after another Husqvarna post
OK
First of all you are doing things the wrong way round.
You ask here first , get told the truth then go on You tube to try and find some one who knows what they are talking about ( cuts out about 75% of them ) then watch how they do it .
If the coil has a remote control unit ( often called an exciter ) then you can test it with an Ω meter and the engine manual will list the limits .
If the coil has an embedded Hall Effect trigger chip in it then it becomes a "Module" and it can not be tested with an Ω meter other than a secondary reading on the HT side .

Now fools skim through a manual and see some numbers then they decide that the numbers for a specific engine must be the same for all engines and publish total BS on You Tube .
Once upon a time I tried to correct some of them but that always results in me being abused, flamed & trolled by the presenters loyal disciples who will not tolerate any criticism of their messiah .

To test a module you need an oscilloscope plus the appropriate signal generators and even a flux generator, thousands of dollars worth of gear to test a $ 40 part .
Now the output of a module gets tested with a variable gap meter
B & S make a simple 2 gap one which gives you a pass / fail result or you can get any one of a number that have a moving contact that can be moved further apart till the spark can no longer jump the gap.
However to be of any meaning full value you need to know things like the number of turns on each winding within the coils the strength of the ignition magnet, the air gap between the coil & magnet the air pressure & humidity in your workshop , your altitude etc etc etc .
So in reality a good / bad test is quite enough
The resistance of AIR at 150 psi over a 0.030" gap is roughly equivalent to the resistance of AIR over a 0.50" gap at sea level .
This is how those old Champion plug testers worked
They had a trembler coil in them that produced a consistent stream of sparks and you increased the air pressure around the spark plug till the spark stopped jumping the plug gap .
A great toy for convincing a car owner that perfectly good spark plugs needed to be replaced

And a word of warning about using those sliding contact spark testers
If you are still generating pulses from the engine and the resistance at the testers gap is too great for the electricity to jump then YOU can become the conductive path OUCH or even RIP so you only widen the gap to .05" or till the spark stops whichever happens first .
I know you’re right about me and you tube. I still go there after figuring out it was not a good place to learn about my outboard motor.
You are also correct about the adjustable spark tester. I bought it for the outboard I was working on. Turned it to the setting the manual said. It was on the back of the motor and I had to get in the boat to pull start the 40hp. So I pulled and it started. I went to lean around to try and look at it instead of getting out(safer).
And Im not sure if it was the bottom cowling the head or what. I have known idea where it came from but I got jump started. I could have sworn I heard someone yell CLEAR and wam I was being lite up like Christmas in the park. My teenage grandson made sure I was ok then couldn’t stop laughing saying you should have seen your face and eyes.
Let me ask you this. The spark I got from the mower wasn’t a good blue it was yellow/orange which tells me it’s weak. The mower sat outside in the elements without being started at least 18 months. Since I checked the spark I’ve taken cover and shrouds off to get to everything and spent most of yesterday cleaning it up and removing corrosion along with taking apart all the electrical connections and cleaning them. After it’s bath I repaired a leaking vale cover and let it set today for the sealant to cure real good. After cleaning the cover I sat it it a piece of clean glass and made sure I couldn’t slide a feeler gauge underneath it.
Also the battery was probably low when I checked the spark which I charged it yesterday while cleaning. I have the new fuel line but discovered that epa vapor hose cracked ever where and after running around tomorrow looking for replacement hose I want to put everything back together and test the spark again. Then figure out how I’m going to get the new hoses hooked up to the fuel tank without removing the mowers body. I just need to get under the fender where you adjust height but it don’t want to budge.
Good job calling me out on those few things. I needed it.
It was a forum like this one that saved me during my boat rebuild. I now know that outboard inside and out. And I have a thick pair of rubber gloves and s set of hose pliers of different sizes with a long reach Incase I want to remove a spark plug wire to check one of the three cylinders.
Thanks for the information. Sounds like the on way I’ll know if a module is bad is if it doesn’t have any fire at all.
 

bertsmobile1

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  • / I’m calling this my one thing after another Husqvarna post
The spark from a magneto is exponentally related to the speed the magnetic field cuts through the coil
At cranking speed you are at the very bottom limit so you get a cruddy spark
You need to test it at operating speeds , that is what is important
You just need enough of a spark at cranking speed to ignite the charge every now & then .
 

Douglasdzaster

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  • / I’m calling this my one thing after another Husqvarna post
The spark from a magneto is exponentally related to the speed the magnetic field cuts through the coil
At cranking speed you are at the very bottom limit so you get a cruddy spark
You need to test it at operating speeds , that is what is important
You just need enough of a spark at cranking speed to ignite the charge every now & then .
Makes sense. Thanks for your reply.
 

Tiger Small Engine

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  • / I’m calling this my one thing after another Husqvarna post
Makes sense. Thanks for your reply.
It is not that all of YouTube is bad for small engines, or any other topic for that matter. The issue is, you gotta sort through the garbage to get to the gold. If you don’t have much knowledge or experience, you may think the garbage is gold.
everytime someone asks about testing a coil (or a lot of other questions for that matter), and Bertsmobile answers by typing copious amounts of typing, that takes time and effort. I’d say some of these questions need to be a sticky. Testing coils is just one step that can be done, it is not definitive usually. The 2.5 to 5 ohm reading is for a 4-5 horsepower push mower engine, not a 22 hp twin.
 

bertsmobile1

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  • / I’m calling this my one thing after another Husqvarna post
Well I did start a thread for people who do know to recommend You tube channels worth looking at and from memory there is only 5 recommendations to date
The current server does not do stickies
 
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