MS201t has poor spark

[Tree94]

the other day while using my ms201t, it just died while ideling. Just turned off by itself.

When I went to start it back up, it wouldn't start.

I verified that the spark plug wasn't sparking. I tried a different spark plug, still no spark.

However, if I use my impact drill to spin the flywheel really fast, it sparks. But it will not spark by just pulling the pull cord. It's not enough.

The ignition coil is like $150. So before I pay that, I'm wondering if you guys can give your opinion on what's causing spark issue.
Thanks!

 

[Little Al]

the other day while using my ms201t, it just died while ideling. Just turned off by itself.

When I went to start it back up, it wouldn't start.

I verified that the spark plug wasn't sparking. I tried a different spark plug, still no spark.

However, if I use my impact drill to spin the flywheel really fast, it sparks. But it will not spark by just pulling the pull cord. It's not enough.

The ignition coil is like $150. So before I pay that, I'm wondering if you guys can give your opinion on what's causing spark issue.
Thanks!

Is your coil the correct spacing from the flywheel ? Should be around a business card but you can close it to 10 Thou or as close as you can without it touching the flywheel the clear plastic boxes that ciookie's /cakes come in from the super market are the correct thickness a strip of that is good as youcan see through it to line up the flywheel magnets/coil slack of the coil fasteners with the strip in place turn flywheel & magnet will pull coil in tighten fasteners & try If no go you require a replacement coil. I have had good success with Huztl aftermarket coils & they are a more reasonable price than OEM

 

[HarleyT]

Your coil is more than likely fine, look at other areas first.

 

[dougand3]

Check kill wires for broken insulation. Anywhere metal wire can get close to cyl and partially or intermittently ground.

 

[Tree94]

I have set the spacing on the flywheel to the thickness of a business card. Still does not work.
This morning I tried fixing it again.
I put it back together and tried starting it. It fired a few times and almost started.
But then the firing stopped and it was just dead again.
I have checked all the wires and the kill wires are all hooked up correctly and show no visible damage.

So what's it mean if it's getting spark sometimes, and other times it's not? It's honestly just sparking at random.
Is that faulty coil?

 

[Tree94]

By the way thank you all for your replies .

 

[tallfarmboy]

Check to see if your flywheel key is sheared. I know that wouldn't affect spark, but it would keep it from starting. I've seen saws TRY to run on a sheared flywheel, but they will barely idle.

 

[HarleyT]

I suggest that you may not have an ignition problem, if you are getting spark at higher revolutions. I would take a peek at the piston condition, check also into whether or not it is flooded, etc.

 

[Tree94]

I suggest that you may not have an ignition problem, if you are getting spark at higher revolutions. I would take a peek at the piston condition, check also into whether or not it is flooded, etc.

Correct me if I'm wrong, but wouldn't the piston condition be irrelevant in this situation?
Compression is already low when testing the spark plug cause it's not screwed in

 

[HarleyT]

I am suggesting that you are misdiagnosing the saw's problem. And the reason your saw won't run lies elsewhere.

 

[HarleyT]

I know that popping off the muffler to peek at the piston is not as easy on this model as other models, but I would suggest you do that before spending any money.

 

[Tree94]

The way I test a spark plug is by pulling the spark plug out, putting it in the spark plug boot and holding it against the engine while I pull the starter cord. If i see spark I assume the spark plug and coil is good.
When I try that now, I pull the cord but see no spark on the plug.
That is why I'm assuming bad coil

 

[HarleyT]

But you will get spark at faster revolutions?

 

[HarleyT]

I'm just trying to save you, and the guy you buy a coil from, a lot of long drawn out headaches......
And money...

 

[Tree94]

But you will get spark at faster revolutions?

Yes. but I will check the piston while I have it apart. Gives me a reason to clean it out too, palm tree gets stuck around the cylinder

 

[Tree94]

I will post my findings soon

 

[HarleyT]

Well, just trying to help. Popping off a muffler is free.

BTW, the retail from Stihl around here for a new coil is @ $90.

 

[vornez2]

Ignition modules have diode semiconductors which are the most common failure points for Stihl chainsaws, hedge trimmers and blowers.

A genuine still MS440/MS660 ignition module has been known to last 20 years/forever and are the most reliable module here.

My MS201t module lasted at least 10 years before packing up. Don't waste your time trying other diagnoses, if you don't see a spark that chainsaw ain't gonna run. But the spark plug does need grounding if it's not in it's hole.

While all the other low range MS180 imitation crap expect them to last about 1 month. You're better off with an alternative brand Chinese knock off unrecognized name.

The bottom range blower - the STIHL BG 56 Blower which quickly clears leaves and grass cuttings and quickly destroys it's own ignition module under constant cycling.

 

[Old2stroke]

Failure to produce spark at lower rpm is a common failure mode for some electronic modules

 

[lone wolf]

the other day while using my ms201t, it just died while ideling. Just turned off by itself.

When I went to start it back up, it wouldn't start.

I verified that the spark plug wasn't sparking. I tried a different spark plug, still no spark.

However, if I use my impact drill to spin the flywheel really fast, it sparks. But it will not spark by just pulling the pull cord. It's not enough.

The ignition coil is like $150. So before I pay that, I'm wondering if you guys can give your opinion on what's causing spark issue.
Thanks!

Adjustable carb MS 201 T or MTronic? I have some parts for the regular ones.