Echo CS 680 stop cutting/running under pressure

[Qasim Khan]

Hi,

My Echo CS 680 stop cutting/running chain when I get in Middle of the wood and chainsaw feel pressure. It's start cutting the wood but stops when it feels pressure and make bog down. I run run perfectly fine otherwise.

To resolve this issue I have replaced new chain and bar, air filter and even carburetor. But problem is this there.

I noticed that there is heat up smoke comes out of clutch side. I have taken the pictures of the clutch and clutch drum. I wanted to get expert opinion if this is due to clutch/clutch drum is slipping and need replacement. If that is true what could be the possible cause of damaging the clutch/clutch drum?
I am attaching pictures of clutch, clutch drum, drum plate and pin bearing.

Thank you.

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[Bob Hedgecutter]

Photo #4 it almost looks like heat bluing from a chain brake band.
Maybe a photo of the clutch laying flat- to see if the springs or attachment points are stretched or elongated?
Some photos the drive hubs for the sprocket look a bit worn and rounded- what sort of condition is the sprocket in?

 

[Qasim Khan]

Photo #4 it almost looks like heat bluing from a chain brake band.
Maybe a photo of the clutch laying flat- to see if the springs or attachment points are stretched or elongated?
Some photos the drive hubs for the sprocket look a bit worn and rounded- what sort of condition is the sprocket in?

Please see the attached pictures of clutch laying flat.
I installed a new sprocket.

 

[cscltd]

Check the exhaust screen, it may be partially or fully plugged,
Also I don’t see a pic of drive rim for sprocket, did you maybe miss putting chain on rim?(however doesn’t look like you missed it?

 

[Qasim Khan]

Check the exhaust screen, it may be partially or fully plugged,
Also I don’t see a pic of drive rim for sprocket, did you maybe miss putting chain on rim?(however doesn’t look like you missed it?

Exhaust screen is clean and there is no blockage. I made sure that chain is properly sitting on the rim sprocket. Chain runs perfectly fine if I am not cutting the wood.

 

[LuDookie]

Do you have chainsaw experience? Not asking to be mean or anything. Just in case… some people might imagine it being like running a power drill. It’s not. With the way a chainsaw’s clutch works, you have to find the power band of the saw and strike the difference between that and having the saw stall against the clutch. I’m sure someone else can explain it better, but perhaps I’m preaching to the choir and you are way past this in your experience and the saw is just running super rich, in which case it will be very doggy in the cut. Is it a new saw?

 

[Qasim Khan]

Do you have chainsaw experience? Not asking to be mean or anything. Just in case… some people might imagine it being like running a power drill. It’s not. With the way a chainsaw’s clutch works, you have to find the power band of the saw and strike the difference between that and having the saw stall against the clutch. I’m sure someone else can explain it better, but perhaps I’m preaching to the choir and you are way past this in your experience and the saw is just running super rich, in which case it will be very doggy in the cut. Is it a new saw?

I bought this chainsaw in Nov-2021 and I have been using it since then.

 

[LuDookie]

I bought this chainsaw in Nov-2021 and I have been using it since then.

Ok, just checking. So it’s never behaved like this? It worked fine before? Almost sounds like the clutch isn’t engaging properly. Does it bog down like it normally would when it stalls against the clutch?

I have the same saw. I sure hope you can get to the bottom of it.

 

[Qasim Khan]

Ok, just checking. So it’s never behaved like this? It worked fine before? Almost sounds like the clutch isn’t engaging properly. Does it bog down like it normally would when it stalls against the clutch?

I have the same saw. I sure hope you can get to the bottom of it.

Yes was working fine and I was keeping the chain sharpen periodically.
this problem started gradually, I thought chain is not good any more so I replaced a new chain with bar. But issue is still there. Saw only bog down when it's cuts the wood and it's under pressure.

 

[LuDookie]

Yes was working fine and I was keeping the chain sharpen periodically.
this problem started gradually, I thought chain is not good any more so I replaced a new chain with bar. But issue is still there. Saw only bog down when it's cuts the wood and it's under pressure.

Strange. A dull chain will usually cause a saw to race vs bog. Sounding more like you might have a fuel delivery problem or like someone else said, blocked exhaust or something. I’ve been running mine steady since 2017. It’s probably been the most problem free and reliable saw I’ve ever owned. Sorry for your trouble but it sounds like it’s just not running right.

 

[Bob Hedgecutter]

Still looks like a brake band burn/scorch/bluing mark to me.

 

[Qasim Khan]

I have ordered clutch and clutch drum. I ll get them by end of the week. I ll install them and try. I will update the results here. Is there anything else I need to check with?
Thank you everyone for your help.

 

[Old2stroke]

How are you at tuning? You may just have a problem with the carb running too lean. Just swapping in a new carb won't cure anything unless it is properly tuned. It's unreasonable to expect the factory settings to be just right for your saw. When a saw bogs as soon as it is loaded, it is usually because of fuel starvation, restriction somewhere in the fuel supply path or a carb problem.

 

[LuDookie]

Still looks like a brake band burn/scorch/bluing mark to me.

Yes, that too. But I’m wondering why it’s running normal out of the wood? Or is it?

 

[epo]

Have you properly checked that it is not a problem with the brake band?
If you unscrew the clutch cover, which is what you screw on with the two nuts when you put on the bar and chain, you can check if the clutch drum fits freely in that visible metal loop.
When you switch the brake lever the loop diameter decreases and increases?




If the clutch springs were overstretched or something like that, it wouldn't cause the trouble at the higher rpm you use when cutting. The problem then could be that the chain would run at idle.

 

[Qasim Khan]

@Old2stroke I know carburetor settings, I tried to adjust the H side of the old carburetor but it didn't fix the problem.

@LuDookie yes it works fine out of wood

@epo I have removed the chain break section just to see if it is causing the issue but that is not the case. Right now chainsaw is running without chain break and stop work after cutting the some wood and as it feels some pressure.

 

[epo]

@epo I have removed the chain break section just to see if it is causing the issue but that is not the case. Right now chainsaw is running without chain break and stop work after cutting the some wood and as it feels some pressure.

While waiting for parts, you can try to measure, for example, with a caliper how much is the inner diameter of the clutch drum. It should not be more than 79 mm (3.11'').

 

[Qasim Khan]

@epo clutch drum diameter is 77.50mm
And I also cheyck clutch diameter which is 75.90m.
I noticed that clutch drum inner surface where clutch engage, is not smooth and it's rough.
Could be cause of the issue?

 

[Old2stroke]

Not likely a clutch issue. The OP is saying the engine bogs when placed under load, that means the engine rpm is being pulled down by the load on the chain, which means the clutch is fully engaged like it should be. If the clutch was faulty, it would slip under load, the chain would stall but the rpm would stay high and the clutch would get REAL hot.

 

[epo]

@epo clutch drum diameter is 77.50mm
And I also cheyck clutch diameter which is 75.90m.
I noticed that clutch drum inner surface where clutch engage, is not smooth and it's rough.
Could be cause of the issue?

Normally, the mating surfaces of the clutch and drum should be smooth, so the fact that they are not is suspicious, especially in the context of the pictures, which show traces of the brake band on the drum. To me, it looks as if the saw was used when the brake band was not opened enough and by rubbing against the outer surface of the drum, it caused high temperatures to be generated, which could also affect the inner surface of the drum.

When possible, I would try to gently smooth this rough surface so as not to cause a change in the internal shape.
You could probably try using Scotch-Brite or fine sandpaper for this.

Not likely a clutch issue. The OP is saying the engine bogs when placed under load, that means the engine rpm is being pulled down by the load on the chain, which means the clutch is fully engaged like it should be. If the clutch was faulty, it would slip under load, the chain would stall but the rpm would stay high and the clutch would get REAL hot.

In the first message he wrote that there is smoke coming from the clutch side.