Saw running with plug wire off!?

[Odog]

Can someone explain this to me? I'm milling away and the saw kinda stutters for a second, but then keeps going strong. I glance at the power head and notice the plug wire is completely off the plug. So I let off the trigger and she goes to idle. How is it still idling away like nothings wrong?

 

[Guido Salvage]

Magic...

 

[Efisher26]

It has to be arcing somewhere, maybe didn't see the spark from plug to coil wire? That's very odd


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Just a home owner that likes the older better made machines

Craftsman 3.7 x2
Husqvarna 36

 

[astnmacgto]

Imagination!

 

[muddstopper]

something may be running on alcohol

 

[Ozhoo]

or it's hot... real hot. Not hot like hot, but hot.

 

[Odog]

I have video of it idling with the plug wire lying down by the handle but I can't seem to get it to upload. I know I didn't imagine it...... I hadn't gotten into the beer yet

 

[TBS]

It has to be arcing somewhere, maybe didn't see the spark from plug to coil wire? That's very odd.

X2 on this. Spark can jump over an inch depending on how strong the coil is.

 

[n240sxguy]

New diesel chainsaw.


Sent from my iPhone using Tapatalk

 

[kevin j]

it's a sharp point inside or a short bit of carbon hot enough can be acting like a glow plug to keep it running. But that typically only happens at high-speed and a heavy load while it stays hot. Specially two-stroke racing engines. How it would do it at idle will be very interesting to see

 

[67L36Driver]

I suggest a colder plug heat range wise.[emoji15]

 

[Odog]

I noticed some melting on the plug boot, which is suggesting the plug was hotter than normal

 

[astnmacgto]

Perhaps it could use a little more fuel to keep it cool, and make sure the cooling fins on the jug aren't all caked up. I would love to see that video, I bet you were like, holy s*** whats going on haha

 

[Odog]

Perhaps it could use a little more fuel to keep it cool, and make sure the cooling fins on the jug aren't all caked up. I would love to see that video, I bet you were like, holy s*** whats going on haha

Oh yeah I was a little in awe, gas engines aren't supposed to act this way normally. I'm trying to upload the video, but I keep getting a compatibility error

 

[alexcagle]

Magic...

*
You need a colder plug, or try a different brand.
*
You've probably got a carbon speck that is glowing red inside the combustion chamber.
*
At Stihl Gold school, I seem to remember they taught us a simple rhyme that "Bosch is bad for blowers", because of the fact that even though it was the correct heat and part number for blowers, there were numberous instances of them continuing running after shut off, with Bosch spark plugs.
They even demonstrated it with a unit that was doing it.
It was strange indeed.

 

[CR888]

Ghost Saw. Alexcagle....what would a colder plug do? Do you believe hotter/colder plugs change combustion temps?? Did they teach you this @Gold-tech school? Not being condescending but interested to hear your answer.

 

[HarleyT]

At Gold Tech school, they teach you how to make your own Light Saber......

 

[67L36Driver]

The porcelain of a plug can get white hot. For example a Champ CJ8 in a saw that requires a CJ6.
Or a lawnmower plug.

BTW: The plug 'gasket' isn't there to stop leaks. It's there for heat transfer to draw heat from the plug to the cylinder head.

Many, many moons ago plugs used a dead soft copper washer.

 

[Boomer 87]

The heat range of spark plugs means how slow or fast the plug tip dissipates combustion heat. Alot of it has to do with insulator shape and size. Cold spark plugs dissipate combustion heat very quickly to avoid pre ignition from having to high combustion temps, maybe what the OP was experiencing. Hot range plugs remove combustion heat slower, typically small engines saws, mowers etc. Use higher heat ranges bc the engine doesnt build high heat on its own so the hot plug is used to keep heat in the combustion chamber longer to avoid carbon fouling. Cold range plugs are used in high heat engines hi performance or race bc they can build high heat rapidly so the plugs needs to get rid of the heat faster to avoid pre ignition

 

[Boomer 87]

Milling saws generate more heat than typically seen in saws so for instance if a range 7 is recommended maybe go to a 6 it would dissipate heat off the plug tip faster. If spark wasnt getting to that spark plug it was dieseling off of like posted a super heated piece of carbon or off the plug tip it self if it were over the temp threshold. However dont just throw any plug in the hole check what manufacturer wants then go from there. Example poulan farm pro 375 requires an cj8 but a 4200 requires a cj4