Where do the sparks that the spark arrestors arrest come from?

[Philbert]

Was looking at some muffler mod threads and got to wondering where the sparks, that the spark arrestors control, come from. Found this USFS info sheet interesting:

http://www.fs.fed.us/eng/pubs/html/03511304/03511304.htm

Philbert

 

[fearofpavement]

Haven't read the sheet but it's from hot pieces of carbon flaking off the piston and muffler.

 

[hillwilliam]

Was looking at some muffler mod threads and got to wondering where the sparks, that the spark arrestors control, come from. Found this USFS info sheet interesting:

http://www.fs.fed.us/eng/pubs/html/03511304/03511304.htm

Philbert

Good info. Also, you can sometimes see little sparks from the b&c, even in clean wood and using a sharp chain, if you've ever had to run a saw in the dark. Or maybe it's just my eyes.

 

[tree monkey]

muffler bearing

 

[huskihl]

Good info. Also, you can sometimes see little sparks from the b&c, even in clean wood and using a sharp chain, if you've ever had to run a saw in the dark. Or maybe it's just my eyes.

Nope not just your eyes. Extremely hard wood, such as ironwood (hornbeam) will throw sparks. Not completely sure if it's from dirt in the wood or inadequate bar oil. Never seen it on maple or elm tho. So idk

 

[Gypo Logger]

The sparks are a direct result of not using 32:1
The sparks may also be an indication that you're about to score.

 

[Full Chisel]

I have seen sparks fly while cutting dry, dead hedge branches...that stuff is gnarly!

 

[huskihl]

The sparks are a direct result of not using 32:1
The sparks may also be an indication that you're about to score.

Jonboy? You bored again? Cabin fever?

 

[Gypo Logger]

No, there is rarely a dull moment around here. Lol

Jonboy? You bored again? Cabin fever?

 

[Philbert]

No, there is rarely a dull moment around here. Lol

Pun?

Philbert

 

[Philbert]

Might have been an airhead moment, but I got to thinking about 'spark arrestors', and I know that they are important. But where do the sparks come from? Air? Fuel? Dirt? Little bits of engine parts falling off? Mommy sparks and Daddy sparks that love each other very much? The carbon thing makes sense, I guess. Hitting stuff in the wood makes sense for sparks coming off the chain.

I don't encourage running chainsaws in the dark, but did test the PowerSharp chain late one evening, when I first received it, and could not wait.
PowerSharp at night
Sparks shoot from translucent case
Two-cycle firefly

Philbert

 

[1Alpha1]

Sparks come from the crankshaft rubbing against the connecting rod.

 

[Chainsaw Jim]

Good info. Also, you can sometimes see little sparks from the b&c, even in clean wood and using a sharp chain, if you've ever had to run a saw in the dark. Or maybe it's just my eyes.

It sounds like you roached the bearings in your bar sprocket.

 

[Philbert]

Sparks come from the crankshaft rubbing against the connecting rod.

Not from using an oversized spark plug?

Philbert

 

[Full Chisel]

I've noticed that the 372 spits quite a bit of sparks, even with a screen in place...not sure why but it runs just fine with a good tune and 40:1 mix.

 

[1Alpha1]

Not from using an oversized spark plug?

Philbert

Well...that too.

 

[hillwilliam]

muffler bearing

I was afraid that's what it might be. It's getting hard to find parts for my old saws, especially muffler bearings. I can still find clutch shoes, but socks are NLA.

 

[Philbert]

The sparks are a direct result of not using 32:1

I've noticed that the 372 spits quite a bit of sparks, . . . with a good tune and 40:1 mix.

On a serious note (if that is possible): if the sparks are the result of carbon in the combustion chamber, would a richer oil-to fuel mix increase this, or only a richer fuel-to-air ratio? Which would cause more carbon?

Philbert

 

[Franny K]

I am not sure spark is the most appropriate term. Smoldering embers or something along that line. I remember one time spectating at a junior enduro, (that is under 18 year old riders, most on 125cc two strokes at that time motorcycles off road) A few of them would come by and then there would be little places smoke came up from the forest floor. I was never able to catch and see for sure what made the smoke but 30 seconds of smoke was not uncommon.

Did you ever do the start a fire without matches by first half burning a piece of I guess it was cotton cloth, essentially charcoal cloth you make the spark with a file and rock or something, the spark makes the charcoalized cloth smolder then you get the birch bark to actually burn from that by blowing. I am thinking the "sparks" are that smoldering charcoalized cloth.

 

[Philbert]

I am not sure spark is the most appropriate term.

USFS document (first post in this thread) calls them 'exhaust particles'.

Philbert