# Spray wd40 on leaf blower impeller and recoil area, now now spark?



## andrewbabich (Jan 13, 2011)

Spray wd40 on leaf blower impeller and recoil area, now no spark?

Hello,

First my recoil would not pull the rope back in.

So I took all the plastic off and sprayed wd40 on and under the impeller, and along the rope recoil assembly that is on top of the impeller area and under the engine. Recoil works perfect now, but...... 

Now I'm getting no spark.... Can the lubricant get up in the magneto or stator area and kill the spark??? Maybe I damaged the spark kill switch wires.....

Its a 1997 33cc craftsman pro leaf blower.


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## chuck_thehammer (Oct 24, 2007)

wait a day or two... yes WD40 can cause electical problems until dried. wil not harm wires but no so good for switches and contacts.


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## 30yearTech (Sep 14, 2006)

It's unlikely that WD-40 caused any issues with the ignition system. I would look for a pinched or grounded kill switch or high tension lead wire, or an issue with the kill switch itself.


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## andrewbabich (Jan 13, 2011)

*good advice*

I want to do that when I go home. 

How do I disable the kill switch. It has two wires that go to it and one goes ground. If I just disconnect it then it shouldn't be able to ground out the spark right?


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## 30yearTech (Sep 14, 2006)

andrewbabich said:


> I want to do that when I go home.
> 
> How do I disable the kill switch. It has two wires that go to it and one goes ground. If I just disconnect it then it shouldn't be able to ground out the spark right?


It's best to disconnect the wire that attaches to the coil/module. If the lead wire from the coil to the switch is grounded somewhere, removing the ground side of the switch won't make any difference.


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## andrewbabich (Jan 13, 2011)

Can you explane how the kill switch works. I can not understand how a seperate wire that gets grounded kills the spark that goes to the spark plug. 

Is it because all the electricity being generated from the coil goes to the path of least resistance which is the seperate ground wire??

Also, if disconecting the wire does not fix the problem is there way to test something else in the electrical system.


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## 30yearTech (Sep 14, 2006)

andrewbabich said:


> Can you explane how the kill switch works. I can not understand how a seperate wire that gets grounded kills the spark that goes to the spark plug.
> 
> Is it because all the electricity being generated from the coil goes to the path of least resistance which is the seperate ground wire??
> 
> Also, if disconecting the wire does not fix the problem is there way to test something else in the electrical system.


The kill wire that attaches to the coil, grounds the primary winding in the coil, preventing it from generating any current to produce a spark. If the the kill wire is grounded anywhere between the switch and the coil, it's just like the kill switch is always in the off position. The kill switch completes the circuit to ground to prevent the module/coil from making spark. If you disconnect the wire from the coil and you still have no spark, then it's likely that your ignition module is bad.

How are you testing for spark?


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## E_Net_Rider (Jun 4, 2010)

Sorry Guys,
I think you have it backwards. In my experience with no starts related to this, the wire from the switch breaks or the switch will no close contacts. That is the switch completes the circuit to ground enabling spark. It does not short the spark to ground.
WD40 may be non-conductive and has formed a film between the contacts of the switch. Washing it out of the switch with solvent or contact cleaner should take care of a switch problem unless the switch has died. It could also be you dislodged some debris that is now between the contacts and blasting it out of the way may solve your problem.
Also think of it as a safety. If switch went bad you would not be able to shut it off wired as you suggest. (nearly all switches fail not being able to close circuit)


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## dehrhardt (Apr 1, 2009)

andrewbabich

30 year has it exactly right. When you flip the switch to the off or stop position, it closes a switch grounding the PRIMARY magneto windings. With the primary windings grounded, the secondaries can't generate the voltage necessary to jump the gap at the spark plug. If the kill switch wire becomes grounded at any point it will prevent the engine from starting.


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## 30yearTech (Sep 14, 2006)

E_Net_Rider said:


> Sorry Guys,
> I think you have it backwards. In my experience with no starts related to this, the wire from the switch breaks or the switch will no close contacts. That is the switch completes the circuit to ground enabling spark. It does not short the spark to ground.
> WD40 may be non-conductive and has formed a film between the contacts of the switch. Washing it out of the switch with solvent or contact cleaner should take care of a switch problem unless the switch has died. It could also be you dislodged some debris that is now between the contacts and blasting it out of the way may solve your problem.
> Also think of it as a safety. If switch went bad you would not be able to shut it off wired as you suggest. (nearly all switches fail not being able to close circuit)


Very few ignitions work the way you describe, most ground the primary circuit of the coil to prevent spark (just like older point ignition setup). There are a few older Lawnboy ignitions (that I know of) that completed the ground to spark and opened it to kill, but that will not be the case on the ignition module used on Craftsman blowers, these modules are internally grounded. It is possible that for some reason the coil may not be getting a good ground, causing a loss of spark. Cleaning the mounting points between the lamination and the mounting posts may restore spark, if the coil is not grounded good, but this ground does not occur through the kill switch. Grounding the primary circuit on the module/coil will prevent spark, an open circuit is needed for spark generation. WD40 will not effect electrical contact to the point of preventing spark, even if the kill switch is flooded with it!


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## E_Net_Rider (Jun 4, 2010)

I must admit memory is very foggy as it was not a profession, but I've worked on a wide array of ignition systems because of necessity arising.
Almost all systems today are integrated to some degree that it is only necessary to do a couple of basic checks on external circuitry and those are OK, then it is the unit itself. Such as with the case here, is the switch lead, connected at the coil assembly working. Are magnets good and properly gapped. Does the coil assembly have proper grounding. Yes to those and you pretty much have to change out the assembly. It lno longer matters whether it is primary circuit, secondary, or timing unit replacing points because it is all internal.
I certainly like the move away from points, now that reliability can be built in.
I had a rotary Mazda with three sets of points. Points wear, the rubbing block wears, and unless you use a dwell meter, you have to adjust timing each time as well. (change in dwell changes timing)
Spark occurs at opening of points, when coil is fully charged. It depends very much upon where the switch is inserted in circuit.
Make sure the switch circuit works, open and close. I suspected WD40 was non-conductive, at least at voltages the switch would encounter. But it still could have dislodged something inside switch unless it is perfectly sealed. Maybe even a little carbon got between switch contacts?


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## andrewbabich (Jan 13, 2011)

Thanks for the help fellas! It works now. I have spark and got it running after letting it sit for five days.

I was checking for spark by letting the plug dangle from the spark plug wire and pulling the cord in the dark while looking for that little blue spark to jump the gap.

I didn't see any spark most of the time, so I held the plug between my fingers from the metal hexagon wrench spot and pulled the cord and then I would see spark.

Why would it spark when i was holding the plug, but not when it was free to dangle in the air without my hand touching it? 

Very confused. When check the spark on my snowmobile, I always just let the plugs dangle from the wires and pull the cord and see that blue spark....

Is there a more professional consistant way of doing this?


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## 30yearTech (Sep 14, 2006)

andrewbabich said:


> Thanks for the help fellas! It works now. I have spark and got it running after letting it sit for five days.
> 
> I was checking for spark by letting the plug dangle from the spark plug wire and pulling the cord in the dark while looking for that little blue spark to jump the gap.
> 
> ...


To check spark using the spark plug, the plug *must* be grounded to some conductive (metal) part of the engine. If it sits against the plastic housing or just hangs in the air, it will not spark. 

The best way for checking spark is with an inline "gap" type spark tester.


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## luckyvision (May 24, 2007)

andrewbabich said:


> I didn't see any spark most of the time, so I held the plug between my fingers from the metal hexagon wrench spot and pulled the cord and then I would see spark.
> 
> Why would it spark when *i was holding the plug*, but not when it was free to dangle in the air *without my hand touching it?*


Really?? REALLY??


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