HOW TO DIAGNOSE A BAD COIL ON JUST ABOUT ANY SMALL ENGINE!

WATCH MY WEAK OR NO SPARK VIDEO HERE

[THEMOWERMEDIC]

WATCH MY WEAK OR NO SPARK VIDEO HERE

[butler]

Excellent information for me. My dad just had me hold the spark plug wire to see if it had spark. Never been the same since. Thanks for the video.

[ronaldfulton]

Phenolic spacers don't conduct a ground connection. Ground for that paricular coil is through threads of the screws.

[johnclarke]

I learned about coils a long time ago. I have a spark tester and it will show me in a second whether the coil is good or bad. I never have forgotten “Blue is good, red is dead and yellow is in between.” This is the color of the spark on the spark plug but it is the same colors given by my spark tester. If the spark is not blue, I put a new coil on it and recheck. The first thing I do check is to see if the bayonet connector is in the spark plug wire.

[tomdale]

you're a badass mehanic, txs for sharing...

[hocstix]

Great video. Can you test the coil using a multimeter alone ?

[cocotower]

I can't find any videos or articles whatsoever on the internet on how to remove that damn motor rotor coupler in order to remove the plastic case of the M2500 trimmer so I can get to the coil. People are calling the shaft coupler halfway down the shaft the "motor coupler" which it is not. The motor coupler is on the short motor shaft itself. I'm sure I have a puller kit somewhere but I need to check before I go and destroy this thing further.

[johnkosheluk]

But if you ask stihl you should check spark with the tester in the spark plug in the unit

[crazeyspivey]

Maybe you can help me on my Echo GT2000. Had real weak spark and would not start. Based on ohm test, coil was bad. Put a new coil on, and totally no spark. Got the gap set right at about 1mm, and even put a new plug in to boot. I will take apart again and clean the shoulder on the 2 coil screws....maybe as you said its just a bad Driving me knuts.

[randyscott]

In other words ; Always buy the extended warranty .

[MrGododgego]

The fact you have no spark after removing the stop wire is the test, you are wasting valuable time.

[philliphall]

Buff the bolts also since it grounded thru bolts and threads

[tombutler]

The coil grounds thru the mounting bolts and not the mounting surfaces due to the phenolic spacers..

[davecross]

I don't understand how corrosion under the coil can hurt spark if a plastic spacer goes between coil and block. Thanks Dave

[ellesmerewildwood]

That's fine if the average DIYer has that spark tester dooverlacky with the internal doohicky. But what about a testing the primary and secondary coils with the multimeter ? Most DIYers have a multimeter.

[ricksanchez]

I am sure it has something to do with the "non servicable electronic components" inside the coil, but have you had any luck spinning a dead coil up with a drill? I have done it two times with sucess out of maybe 10, one I actually watched the spark become more intense. The one is on an old FS76 trimmer that I gave $3 for. The coil is "obsolete" (but not really), I still use it 3 years later. I thought it was BS when I seen it on a vid, I'll testify to it now.

[nsot]

Im still waiting for my plane ticket to come down and hang out with you for a few I'm all packed and ready to go!!!! Great stuff MM1, as always!!!!

[TheReal]

But it's the bolts/threads that make your ground on the coil to the engine, not the shoulder of the holes. Those spacers eliminate that shoulder-to-shoulder contact.

[mr.hanger]

Business card? Dang, I've been using a matchbook for years. I must rethink my whole life!

[johnrobertson]

Thanks for making all your videos...but you know, the rubber washers are for vibration isolation...and no amount of polishing of the coil mounts will affect the coil with an electrically insulating piece of material! 🙄...the magnet on the flywheel moving past the coil is what makes the spark, it’s a micro generator...and the kill switch connects to the flag terminals...there is no need for the coil to even contact t the engine...but even if it did...the mounting screws are metal and would provide continuity...so probably you lucked out and even if why you think the coil needs to touch, there may have been corrosion in the screw threads...also...you should show the need to ground the electrode of the sparkplug...that is where you need continuity...otherwise even a bad sparkplug will cause your tester to not light...we had two instances of this issue on two blowers...