6421 question

I ran my 6421 tonight and noticed a couple things that I'm not used to on my husky.

Both things have to do with the muffler; one is the left exhaust port does not have what looks like a spark arrestor on it, it's just a hole. Sparks occasionally flew out of this exhaust port today, something i've never seen before, is it normal?

and the second thing is, the screen on the muffler, located onto to one side, it got cherry red today too, is this normal?

My first thought was the muffler is getting clogged and is heating up too hot.

 

The sparks without a spark screen are normal. Don't know about the screen, never paid attention to it. Maybe Moderating can move this to the chainsaw forum.

 

screen is spark arrestor for those chunks of glowing carbon. that muffler has a cat in it which is why it runs so hot. so the basic mod is to open up muffler remove cat increase muffler exit port size and retune saw afterwards. There are details floating around on how to do this. Benifits - the saw will come alive and exhibit more power, run cooler. Oh and brand new out of the box the saws are tuned way to lean ( all makes) in the first place- Thanks to the meddling EPA.

 

I'm confused .
The stock muffler only has 1 exhaust port

 

Maybe I'm mistaken. The two holes facing directly outward are not the exhaust ports?
and then facing the saw, in the top left corner is another port covered with a mesh screen.

The two round ports in front have some kind of diverter (arrestor maybe) in the hole itself
this is where my sparks would come from. One of the ports on mine has no diverter in it, this is the port the
sparks came from.

The screen at the top of the muffler also got cherry red while cutting.

 

Is the cat inside the muffler becoming clogged already with what I've described? Should the muffler parts be that hot?

The other things that happened was a few chips were lodged beside the muffler and caused a small smoke show when I was refueling.
First time for that too

 

Is there a chance that a spark could come out of the hole on the right? I was cutting and saw the sparks fly couldn't see where they came from but a buddy of mine was watching and pointed to the hole on the right. I'm just trying to make sure, I'm sorry if I sound like a nag.

 

So there are two bolts in those two round slots and the two bolts that are on the front below those?

 

I ran the saw in nothing a few times just to see what your asking. As I revved it up a couple times I could see a couple sparks come out.
I wasn't sure when it was in wood whether or not I was hitting some dirt of something else so I ran it dry and revved it, still got sparks

 

I'm with Dex I find it hard to believe that the stock muffler is making the sparks. The bolts holding the muffler on are torx style heads. If you don't have a set of torx drivers, China Fright (Harbor Freight) sells a set cheap. If your used to a spur type sprocket;

Its easy to install the chain improperly on a rim type sprocket until you get used to it;


I've seen sparks thrown from an improperly installed chain. Maybe you can shoot a video of said sparks?

As far as the screen getting hot it's typical for a muffler with a catalytic converter to run much hotter than one without.

 

Clean the saw up , give it a good blow job , clean the bar groove , check bar for damage and check if chain is on sprocket right , tension the chain properly , start it up and see what ya got .
I never noticed my screen getting red hot but , never really looked

 

if you are fat on the oil mix or not the right oil could be a bit of carbon build popping loose , Or because it is a new saw maybe some plating from the muff just burning off. Just musing here.

 

I'm starting to lean towards the sprocket idea. Although I have yet to get at it today.