Test Any Ignition Coil With A Multimeter! (Easy DIY Tutorial!)

Tutorial on how to test ignition coils you’ll find when repairing your engines at home regardless of brand. Honda, Kohler, Stihl, Husqvarna, Briggs and Stratton - it doesn’t matter! With a multimeter in hand, you can follow along with this in-depth, step by step tutorial! I cover the entire process from start to finish including interpreting multimeter readings, pitfalls to avoid as well as revealing a crucial, often overlooked step that can cost you hundreds of dollars too. Learn how to account for variations in resistance values, ensuring an accurate diagnoses as well as gain insights into recognizing the signs and symptoms of failing ignition coils, helping you prevent miss diagnoses, unnecessary expense and time too!

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#multimeter #ignition #smallenginerepair #resistance #ignitioncoil #honda #briggsandstratton

00:00 Use a multiplier to test an ignition coil
00:51 What you need to test an ignition coil
01:00 What is an ignition coil?
01:33 Good resistance values of an ignition coil
03:15 How to test and ignition coil with a multimeter
05:44 Don't make this mistake when testing your ignition coil!
07:21 Reasons why you may not have spark
07:51 Symptoms to look for when diagnosing a spark fault
08:22 My favorite spark tester

[VintageEngineRepairs]

If this video helped you, please consider clicking on the THANKS button above to support my channel 🙌

[gerrydepp]

I had my own workshop for 30 years and murphy was a constant companion so more often than not there was more than 1 problem or inconclusive. If I had a buck for every coil I tested that had good values but was crap....in the end I gave up these tests, it is only an indication ie if the coil is crap this will confirm it...or not. The most useful test (and fast) if the motor is running - but has an ignition problem - is to remove the cap from the coil and start the motor while holding (and being very careful) the end of the lead to the plug or earth if you have more than one cyl. The spark should be fat strong and blue and most importantly should easily be able to jump about 6mm. As you are holding the lead you can easily vary the distance and if the spark faulters and or the engine stops as soon as you increase the distance the slightest from the plug you know that either the coil is faulty or there is not enough power (dodgy electronics normaly wont let the engine run at all) - you have to then eliminate the plug first too of course but most often it is the coil. But if the spark and engine is still going strong with sparks an inch long you know the coil is not at fault. The next test is then the magneto coil (or with a battery ignition simply to measure the voltage at the coil - this will be pulsed if the electronics are not in the coil). Also here there is little point in measuring the resistance thru it as what makes these tests so inconclusive is a broken down insulation not bad enough to open or short it but just enough to allow moisture to get in. This then shorts it as soon as voltage builds up - same goes for the ignition coil. So you need a peak voltage meter which can be bought cheap and put in series on your multimeter. This then allows the multimeter to accurately measure the very short voltage spikes put out by the magneto and immediately shows up any problems with power supply as a high enough voltage of about 90 - 200v AC will not build up. You need to confirm those values depending on what bike/other you have as that is just from memory and I am retired now! There are also measuring charts for assessing the electronic parts but they can be hard to get right as they will vary depending on which multimeter you have. Sometimes all you can do to verify those is to employ a process of elimination. The best part of this vid was how he eliminated the TCI part of the coil from the test - well done. Hope this helps someone! All the best from Aotearoa

[Jay_Ira]

Thanks bud. This video is timed well because I've got a saw I believe has ignition issues. This is a big help. May God bless you and keep you.

[TheLawnmowerLady]

Nice video Tom! Lots of great info. I need to watch this again.

[horserider]

Probably the most informative and well explained i seen.

[isaacpierrelawrence]

If anyone is wondering about the tree behind him it's a wallum bottlebrush... Anyways...

[clivebeswick]

Finally someone who knows what they are talking about !

[mikec]

thanks for a very well prepared and executed tutorial. Not a moment wasted! Not a single umm or errr. I learnt more than ever about this diagnosis. In my case it was a faulty ceramic resistor in the sparkplug boot. Not cracked. Looked a tiny bit discolored. Found after all the hassle of an engine pull-down for coil testing

[ericroman]

Fantastic video. I was ready to look into buying new coils because of off readings due to my amateur mechanics. I didn't know I should chose the lowest ohm setting for primary testing and it didn't occur to me to subtract any prior ohm showing before the actual test. Thanks man.

[haneyoakie]

Good information well delivered. Thank you Tom. I will be referencing this video again and again. I bought a box of coils at auction dirt cheap. $20 for about 20 coils, mainly Briggs Quantum and Classic types by casual observation. I will be testing them to see which are keepers.

[orweyztungchiu]

Very comprehensive coverage on ignition coil testing - wish I had seen it years ago. I'm thinking I've thrown out many good ones based on faulty testing criteria. Cheers

[joe-fix-it]

Awesome video, great explanation on how to test the coil and where to set the meter. Thanks

[BalGo]

Another great video Tom! I have been testing some Stihl coils and I was getting those weird readings. I’ll be sure to check them again.

[mp]

Can you add and electronic diagram of the coil spark plug the see all the components? Maybe there is a darlington transistor inside of the coil. Who power the darligton transistor base?

[nickush]

I think that I have thanked you before, and if so, never mind !! Thanks Bro, I had this video saved ready for when I needed it, and today, I needed it, and now that I have actually done it, I will most likely remember it.... Thanks, again again....

[Big_Johns]

Nice job Tom, thanks for the explanation. 👍

[mrpearl]

I saved this one Tom I want to give this a try ! Not good at the electrical side of small engine repair 🤷

[michaelspencer]

Excellent video. That's more about an ignition coil I've heard from anyone. Thanks 😊

[mikespain]

Excellent explanation, I enjoy your channel. I have replaced several ignition coils this year for customers.

[treecycle]

Will tuck this one away for future reference. Thanks for all the info you provide for us.