572xp spark issue

[beamero]

I have a 572xp, about a year old. Used it yesterday, won't crank today. Very very very (if any) limited spark on multiple spark plugs. I figured out that if I hold the switch in the kill position, I have full spark when pulling the cord. Any suggestions on what may be wrong? I was sure it was going to be the coil until I discovered the switch. 

[barbender]

It sounds like a switch issue. Try bypassing it.

[beamero]

Looks like it pushes a metal spring-like wire down to coomplete a circuit when pressing it into kill position. This switch looks to be always open until pressed, so I'm not sure on how to properly bypass it. It has a wire terminal to the bottom, and with it unhooked, spark is completely gone, no matter what position the switch is in. 

[moodnacreek]

It won't crank? I think you mean it won't run. You would have to crank it to see the spark. My 575 coil was bad when the saw was new.

[Spike60]

Think you are getting side-tracked with this switch deal. But it would be interesting to see how you are pulling the rope while holding the switch and observing the spark.

Coil has been updated recently, and I've warrantied a couple of them. Some of the original coils were sourced in Mexico. New coil is from Sweden.

There are no service bulletins or such. But if it fails, the new one is improved. Not a big deal, and no reason for anyone to lose sleep waiting for their coil to fail. I've seen TWO failures in about 200 saws. 1% ain't a big problem

[rusticretreater]

As I understand it, a kill switch usually grounds the secondary electrical circuit of the module so you have no spark.  The kill switch itself is usually a simple mechanical lever and really can't fail. And yes the metal spring should be in open circuit when not pressed on.

To bypass the switch and mimic the kill position, simply take a wire with alligator clips on both ends and connect the metal strip to ground.  This is the same as pushing on the kill switch. Without pressing the kill switch check for spark and if present, then the system is shorted.

All the wiring on the carb side of the white connector should be examined for damage.  The wiring on the other side of the connector goes directly to the module.  If all wires look good, you need a new module.

Just take the module to a dealer or shop and ask them to test it. Take your purchase documentation and show that it is not an old saw.  They will be eager to help.

 

[Spike60]

Some shops might be eager to help.

But don't remove the coil from the saw. You need to bring in the whole thing. I don't know of any way to test these coils. But the first thing any dealer should do is plug the saw into the CST and see if there's anything going on. Plus, this will show exactly how many hours are on the saw. A lot of the info available when you hook up the saw to a computer needs to be entered on a warranty claim. Further, a firmware update/fuel setting reset can be done at that time.

Only seen it once, but there is an error code for a short in one of the wires which happened to be where it passed through the case, so this AT stuff can be helpful.

[beamero]

Thanks much. I'll check for wire damage and potentially take it in for further diagnosis. 

[DHansen]

If I was trying to diagnose why this is not starting, Here is what I would do.  Remove the spark plugs from the cylinder.  With the plug removed the saw can be pulled over easier and faster.  Then check for spark with the kill switch in the normal operation condition.  Confirm if you have or do not have consistent spark.  If you have spark, confirm the spark can jump a .040" gap.   Your plug gap will be about half this distance.   If no spark, unplug the kill switch.  The kill switch interrupts the primary ignition circuit of of the ignition system.  This interruption of primary will prevent any secondary output from the coil.  Test one item and one system at a time.

[ehp]

Do what Spike says and your saw will get fixed, anything else is just a guess at best