You're the first person to come close to showing what primary and secondary mean. So thank you for that! You say a coil can pass the test but still be bad -- I paraphrase, and perhaps even misquote -- for which, apologies. I seem to have the opposite!! It works --- only when I removed the kill wire (then had to kill the engine by closing the throttle) -- but when I did your test the primary was showing 1.2 (and continuity beep), the secondary was showing 7.5 ..pfeef..nothing.. I've just pulled the wire from the cap hoping to bypass any problems the cap or its fitting to the wire might be posing, and middle, the business part of the wire which is tiny just seemed to come apart. The wire and it's best sheath (I suppose?) seemed okay. I had tested the kill/on/off switch and that was okay. So these HT leads are deceptively fat -- mostly rubber with one tiny strand running through the middle. How come the prong(s) on the coil in the cap actually meet them??? Well, the wire is moulded into the coil so I shall now search to see if any brave soul has made that venture! The only place I can find a coil with 52mm centres is... China. Cheap but 3 weeks. Still using sampans out there? Well, to make the story even longer, a few years ago I put an inline so-called spark tester in, pulled and the thing started! Removed the tester. No start. Did this several times, each time it would only fire up with the tester in! What would the neighbours think?! Can't remember exactly but think I ..yes, I removed the cap, just left the little fixing coil. Forgot several times to my shock when starting up bold it down the hard plug. Strapped a bit of rubber around it. Finally put a new plug on last week. Lent it to neighbouring farmer ladies working. Came back not. Thought I'd solved the problem when I discovered the bulb wasn't sucking up petrol -- broken pipes renewed. THE END (with apologies).

After 1 week of specification searching this is the first video and documentation in general where I could find the coil resistance... The whole internet is void of this info... Nothing but generic codes... Thank you for this info!

Spot on brother. One of my coils was suspect; however, when tested, it would show that it was good. Your comment about a coil testing good, but still being bad was exactly my situation. Good video!

I had very erratic coil resistances on my Echo coil. I came close to throwing in the towel and buying a new one for $80 but I thought I needed to understand how to remove the boot if I got a new one so I went through a dry run of removing the spring and boot and snipped off a little bit of the wire. Reinstalling the sharp point back into the into the wire and putting it back through the hole and testing solved the problem. Not sure but guessing the connection was poor there. Always redo the connection before getting a new one. Saved me $$$. Great video - thanks

I'm in coil hell... I've three saws now that have good clean carbs, new plugs. When I spin the saw to see how much spark there is, I get reasonable spark. Once the plug is back in, the saws don't even kick, even with starting fluid. Not even a pop. I pull the plug, it's wet... which I believe is also a tell-tale. All these saws were running great. While using them, they died, never to be started again. I need my big saws... I've tornado damage to clean up. I just ordered new coils today... will see. I appreciate you using a VOM... that's what I was looking for. Thanks.

The phantom coil you mention it seemed ok but was going bad.... coil packs are affected by heat. Usually they are cold when you test them with multimeter..... If you pop them in the oven at 100 deg C for 10mins and then test them, you'll find the phantom coil !!!

Thanks for that info at the end of the vid, I had one doing just that. The spark would go weak after 10 minutes of running, gave the symptom of losing fuel. Changing the plug for a new one which made it run for longer was was the only clue to what was wrong.

If you've mowed 10 times this season, then both sides refuse to fire one day, what is the likelihood that it is both coils??? In the event that the coils are good, what are other possibilities ?? I have already inspected the magnet and done a small bit of sanding.. on a 2006 Lazer z I am guessing that it has one ignition pack to supply the coil pair... (???)

i have a 89 ninja zx10, i have a dyna 2000 ignition on it and it has a red indicator light on it and i noticed when the light is on the bike fires up, when its not on it wont fire up. Checked my plugs and i get no spark, got a multimeter and checked coils, primary and secondary. Manual says primary should read 2.6-3.2 and it does, secondary should read 13-17 ohms. My coils are plugs 1 and 4 and 2 and 3, they both read 22-26 ohms, should changing my coils cause my bike to run again?

Thanks for posting. When they do go bad,don't they usually just read open? I see a lot of guys just throw on a new one without checking continuity.

Hey love the video! I have replaced my ignition coil however when I short the coil it should turn off the engine. (Kill switch) but it doesn’t. I tested the kill switch and it’s giving ground to the coil. How would I test the coil? Any help would be great.

2:00 how do you fix this bc this is what's wrong with mine

Where do you find the resistance needed to test the coils is there a website that list all the coils and shows the ohm reading requirements?

can you test it on the unit or do you have to take it off? GREAT STUFF!!!!!!!!!!

what is the resistance value of primary and secondary coil

can you do this test with the coil still in place? or do you need to remove it from the engine? great video btw. straight to the point. You're my kinda guy

Hello I have a chainsaw homelite 340, its coil ignition burns, I have not found on the market a replacement for the same model, can I use another model of a other brand? thanks for your vide

This is a great and old school bench test. If it tests well on the bench, that's where it's nice to have a lab scope to check spark firing patterns (automotive)

How many volts does that coil produce?

I think my SRM 230 coil is bad. Pulled it. One side has a measurement of 330 ohm, the other side is 2.2k ohm. Doing the sparky test yields no spark 99.9% time, gave me one tiny spark during one of the pulls, but it's mostly dead. The trimmer started like a champ for the season, but died within the first minute during warmup, then stayed dead. I also checked the Stop switch and wire inside the handle, and these look good and have continuity with switch is in Stop. Had to convince myself it was ok to buy a $43 OEM part.

Where would one find the resistance specifications for a ignition coil for a Tecumseh OVRM 55 engine? I have found a replacement coil but how do I know the specs to check the old one. So far, the old coil has no readings for either the primary or secondary.

Guys, remove the plug cap before measuring the secondary coil resistance as plug caps like the one in the clip are usually suppressor types ie there to suppress RF (radio frequency) noise. That's the noise or video interference you hear/see on a radio/TV etc. These type of caps are either, zero ohms, 5 K (5 thousand) ohms, 8K or 10K. You should also check the plug caps are good, ie not open circuit or more than 10K.

Hi, I have a Mc Culloch ProMac 650 and it has a poor spark. How do I test my Ignition coil ?Thank you in advance.George

hi there i have a question for you i have echo chaisaw which i check the coil the primary give near 800 ohms and secondary 1.53 k ohms specs from says 200-400 ohms primary and secondary 1.5 to 2.2 k ohms is my coil bad ??? the saw wont start . thanks !

Bit high on primary side is it ok

Thanks for the info, I had no spark with a new spark plug on a 1978 Homelite XL chainsaw and I suspected the coil. I just checked it with a meter and came up with 2.3 ohms on the primary and no reading at all on the secondary. I even took the plug wire out of the coil and put the lead directly to it. I guess it's time for a new coil but NOS coils for this saw run about $40 and I've read bad reviews about some of the cheap coils so not sure what to buy yet.... I'm researching coils now.

I have two sthil ms250 chainsaws. Both will not show spark. Have replaced one with a new one and still no spark. All wires appear to be correctly wired, I found the resistance specs in the owners manual, Resistance from spark plug boot to ground is 1.5 to 12k ohms and ignition lead to ground is less than 10 ohms.

Could you please tell me where the 2 spark plugs are on the alstar boss 250cc ag

Maybe say what may happen with a coil that reads high on the secondary.

Jerry, I have a question for you. I have a Craftsman leaf blower. The ignition coil, and the spark plug gets very hot and a little after I turn it off, it starts smelling to something burning and Smoke comes out fron that area. I replace the spark plug but it is about the same. I wonder if it could be the ignition coli that is worn out

Is it a bad coil if the tester shows spark but when the plug is installed in the tester and grounded I get no spark...bad coil? Used 2 new spark plugs, same problem. Any suggestions?

Where can I find the specs for a Kawasaki coil #21171-0711 on a FS600V AS1177 engine? Thanks for showing the testing technique!

I was getting the same reading of 10.ohms and no spark, same exact looking coil on a Kohler RH265 engine

How do you get the specs for that certain coil

Hi! Great video! A couple of years ago I bought a BS power generator that has been running great until last week. It ran for 3 hours and then stopped and Doesn’t want to start up. I put fresh fuel, I cleaned the carburetor jets (everything was really clean and brand new), I also tried spraying some gasoline through the carburetor and also with a a quick start spray without luck. The spark plug is making a nice and strong spark arc, the oil level is fine as well as the sensor. I checked all the cables and everything seems fine. I just don’t know what else to do! If there is spark (and a strong one) and there is fuel inside, why isn’t it starting? Oh and when I pull, there seems to be good compression... Any ideas? Thanks!

My power pro start and then shut off after few seconds. What is the problem? I got new spark plug and new carburetor and new gas.

what would cause a coil to fail repeatedly within a short period of time after replacing it with factory parts not aftermarket junk? Thanks

I have a FL 822 Honda coil and i cannot find the reading specifications on this coil on You Tube or anywhere. It goes on a lawnmower engine, a Honda. I get 17.2 ohms from the spark plug end to the ground. Is this right?

I have a GX670 that needs the left coil to be warmed up before it will fire, indicating bad wiring in the coil that connects once it warms up. Apparently this is a common issue with many Honda small engines.

On a gc160 honda when u try to start it it's backfires or spits through thr carburetor. The old coil checks at 18 to 19 0hms primary and secondary I say it's defective. The brand new one secondary reads 6.90 ohms the primary reads 000 so is this coil bad

I have a Echo hedge trimmer HC1500 what is the speck on the coil cause I cannot find it on the site

My Echo trimmer would run for a while then die. Wouldn't re-start so I give it a 5-minute rest then it will crank again. Turns out the ignition coil was bad. After putting in a new one, it will now start every time after turning it off. I suspect something inside the coil would open the circuit when it heats up. So if yours have the same symptoms as mine if it's not the spark plug, it's the coil.

Thanks for sharing, good to know. - take care

How do you get the manufacturer readings for a Strimmer coil

Bought my 80 cc online haven't a clue on manuf. specs don't know who made it but I've switched coils since but it's still dying in middle of my ventures so I'm peddling 3-4 miles back home to try again what the problem is ... How do I know which plug wire and cap and plug to use with the coils I have?

why do you hide it under your sleeve? cant see what you did.

Excellent presentation and content, here!💯

How to make the coil works and the plug spark outisde the vehicle?

happens to me too check to test its good but when it runs it goes bad and goes weak and missfires but at low speed its good at high speed it lose its power

I have a Husqvarna 325P4x pole saw. Very little (weak) spark and sometimes no spark. Just purchased a new oem coil from Husq. Now I get no spark. Any thoughts. Thanks.

DID a twin Briggs and coils test good no spark

Thank you this was Actually helpful ! Now i understood the connections , ive been troubleshooting my freshly bought hva 444sg chainsaw from 1986 with no spark issues i already have a hva 44 from the same era with the exact same ignition coil that one works perfectly and the 444 had no spark at all after testing with the multimeter it actually reads almost the same digits ! So then i know there might be some Tore cables Or the Generator/alternator in the 444 sonil switching the generator to see what the difference is Hopefully i dont have to redo all wiring in the saw . Thanks for the tip this saved me roughly 180$ for that igintion coil they only made that coil for the 44/444 Truly Annoying . Regards Paul-Roger

Hi my ignition coil spark is jumping out the wire and hitting on a chrome plate I have a predator 212 do you no what it might be do I need to replace the coil ignition wire thank you

Come on I'm trying to find out wher to put the leads, iron core ? Is that frame or ground thanks

I like to unscrew the wire and check separately from the coil. When testing the coil if it's acting up when the saw is warm only - just use a heat gun set on low and heat the coil - then test again I've caught many bad coils that way. Use Stens or OEM - the really cheap chi coils will fail 90% of time.

Hi on my 08 Polaris 700 cfi on the pto side plug dose not fire when the boot is on and when I pull the boot off and hold it on the side off the plug is starts firing and runs properly and when I put the boot back on it stops firing Any ideas what's goin on there ???

Dude I came here for you to give me the specs I can’t find shit anywhere for this damn Kohler 1458404 coil

can a multimeter read rpm from the coil i hz ?

w When testing a coil it may show good when at room temp and go out of spec when it starts to heat up. You may need to put it in a toaster oven for about 5 minutes at 150 degrees and then redo the test. The coil can go out of range when it warms up, causing it to stop producing a spark.

Hi i have a when power 2200 generator it just died on me all of a suden i pulled the spark plug and tested to see if it had spark it only sparked once or twice very week spark. If the coil is bad doesn't that mean there would be no spark at all it ran great then just died .i need it cause we got hit bad by irma

Great job

This is very interesting because I have been watch numerous videos and ppl are checking 2ndary differently. One person checks the iron core another checks the pin. So everyone isn't right

You could have a broken wire in the coil. Years ago in my case I had a condenser that worked when it was cold, when it ran for a bit it stopped. I bought a new condenser and no problem. Just saying, coils have tiny wire inside and they can break.

Would it be wise to also try testing the coil after it has been warmed up take the car for a little bit of a drive turn the car off and immediately test it that's it obviously you can't test it while it's running but this way you can test it when it gets hot because that's when the resistance can be lost

How much voltage goes into the primary?

What does the primary do? Does it prodices low voltage?

Thank you for getting right to point

check out Ken Bohn video How to check a magneto with a flashlight battery this way it take all the guess work out coil testing, you get a spark at the spark plug!

My mower will start and run just fine but it wont die even if I take the pig tail from the coils and ground them to the motor or any where else

If the coil works when it is cool and dose not work after it warms up is most likely the expansion of the material as the coil warms up. To help explain, imagine a break in a wire which it in a tightly confined space (like wraps in a coil). While in the cool state the wire contracts which makes the connection between the broken piece(s) of wire but as the coil heat up and expansion of the materials pull the wires away from a sufficient contact. At first the coil may run within spec but as the it heats up the coil may fail right away, or lose power, backfiring and will eventually stop working and you and your Harley are stranded on the side of the road.

So I had my dirtbike blown and then I unplugged the boot and plugged it back in and it started for a second hesitated then shut off what's my issue ?

Tempreture increase causes expansion and wire to separate and loses it connection in that windings

Current ramp with oscilloscope with coil firing or heat gun with multi-meter only reliable test . Cold test with multi-meter is not reliable like you said

I get 1.4 ohms on the primary and 6.4k onthe secondary. 590454 BnS coil. No spark whatsoever

I checked all the coils they all worked but the 4th coil pack isnt igniting what would that be?

I have an 80s Yamaha g1 gas golf cart runs good in reverse nothing in forward I have changed solenoids starter generator checked all wires and can't figure it out the coil is newer but don't want to buy another unless I know this can be the issue I hope so this cart has ran good for years my d9said it popped them nothing in forward but reverse runs good any one ever have a similar problem that could help me thanks

You should check with a Megger to tell if insulation breaks down.

just tested mine on a weedeater ultra-trim unit. wasn't sparking. I could feel a slight tickle when holding the plug while it was grounded to the head when turning it over. I cleaned the contacts on the coil and on the flywheel. reset the gap between to .010" but still not sparking. changed plugs. I put a multimeter on the coil and when on Ohms setting, red to the metal on the spark plug boot, black to the metal part of the coil. registered 4.89. when I did the red on the plug-in clip for the kill wire, black to the metal part of the coil, register 224. that seem normal?

Does it matter if the coil is on the chainsaw or whatever? Do I set the meter on 20K? What about if the coil is older and the wires are cracked or frayed? Does that matter?

Good video. You should let people know where to set there multi meter.

c9148 coil specs?

Good informative little video. Tumbs up for you from Pakistan.

Cool job

What is the symtom for a bad coil?

Ad to this you have to have the spacing between the coil and magneto, on the flywheel in proper spec. About 10 Thousands. Business card works .

Have a brand new coil that shows no resistance/continuity on the secondary(plug boot to coil magnet) circuit.

nice video. thanks

How bright spark should be? I bought one of those spark tester ($5 ~ $7 harbor freight) and it sparks ( orange or amber in color) every time I pull (about 100 times). But I can't get it to start.

why would my primary be at 23

THANX

ty

You can ring coil with a scope and it will show if even 1 turn is shorted.

dont foget to check it hot say 250 . and not in a microwave

Good test after replaying a hundred times because your going so darn fast

This is not foolproof. Ignition modules have semiconductors that can go bad. The coils will measure properly but the spark will be weak. The spark may ONLY exist at high RPM. You need to have a good spark at pull cord speeds.

It’s a shame we can’t see exactly where you are checking, and which places you are touching the probes to.

What is "a ignition coil"?

You need to make sure the sound is not dropping out

Good info !! Thanks !!!

Be nice if we could see it. You could turn the lights off and do it next time