Echo CS 680 stop cutting/running under pressure

[LuDookie]

Are you using the same bar as always? Same chain?

 

[Old2stroke]

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.



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

When the saw "bogs" and pulls the rpm down it will reach the point where the clutch starts to slip and he is probably keeping the power on with the chain stalled and that is what is heating the clutch. Pilot error.

 

[Bob Hedgecutter]

H

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

How about some photos of the bar and chain?
Close photo of the chain cutting tooth and relationship to the depth gauge be good.

 

[Old2stroke]

Just to clarify "bogging", are you saying that you can rev the saw up to full cutting speed but as soon as you stick it into some wood, the rpm gets pulled way down and the chain stalls?
If the saw runs well and will rev up and run the chain normally with no load but doesn't have enough power to pull the chain in wood, this is not a clutch problem. When it "bogs", if the engine is still running with the throttle held open and the chain is stalled in the wood, the clutch is slipping and all the power of the engine is showing up as heat in the clutch.

 

[epo]

When the saw "bogs" and pulls the rpm down it will reach the point where the clutch starts to slip and he is probably keeping the power on with the chain stalled and that is what is heating the clutch. Pilot error.

Normally I would suspect that too, but in message #9 he wrote that he put on a new bar and chain and that didn't help.
And based on his posts it looks like he was able to handle cutting wood before the problem occurred.

 

[thompsoncustom]

the title says "stops cutting/running" so is the saw dieing under load? Problems with the impulse line can cause the saw to idle and run WOT out of the wood ok but die under load seen that before.

 

[epo]

the title says "stops cutting/running" so is the saw dieing under load? Problems with the impulse line can cause the saw to idle and run WOT out of the wood ok but die under load seen that before.

If it was dying, there would be no smoke coming from the clutch side. From @Qasim Khan description, it appears that the clutch is slipping. Now only need to pinpoint the cause of this. The clutch drum shows signs of overheating from friction against the brake band. Overheating is also visible on the clutch shoes. The inner surface of the drum is also not smooth.
Maybe in this condition the clutch/drum is not able to transfer the engine torque needed for normal cutting.

 

[Old2stroke]

If it was dying, there would be no smoke coming from the clutch side. From @Qasim Khan description, it appears that the clutch is slipping. Now only need to pinpoint the cause of this. The clutch drum shows signs of overheating from friction against the brake band. Overheating is also visible on the clutch shoes. The inner surface of the drum is also not smooth.
Maybe in this condition the clutch/drum is not able to transfer the engine torque needed for normal cutting.

The clutch is slipping because the engine is bogging down to the rpm where it SHOULD slip and you only have to keep the power on with the chain stalled for a short time before it overheats the clutch.

 

[pioneerguy600]

The edges of the clutch shoes in his pics are blued,evidently the clutch is slipping.

 

[chilipeppermaniac]

H

How about some photos of the bar and chain?
Close photo of the chain cutting tooth and relationship to the depth gauge be good.

I also was curious about the chain and bar itself, especially the groove. Begin with the saw off and a properly adjusted chain. Manually move the chain to see how freely it moves. I am looking for binding scenarios here. Next, take the chain off and look down the rails on both sides. Pics for us won't hurt here too.

I think these areas have been mentioned but I will list them and others as they hit my head.

Fuel Filter in the tank.
Set the L and H screws back to factory settings ( I saw you say that you adjusted the H)
Confirm status of Chain, Sprocket, Roller nose being free, ( Another member mentioned that he has experienced maybe 3 locked up noses)
*****I see that you installed new parts ( chain, sprocket, etc.

Air Leaks
Fuel Lines gummed up
Brake band operation
Air Filter
Spark Plug Fouling/Spark Strength
Muffler Screen
Carb clean/blockage

 

[epo]

The clutch is slipping because the engine is bogging down to the rpm where it SHOULD slip and you only have to keep the power on with the chain stalled for a short time before it overheats the clutch.

The problem is that we can't be sure from these posts whether the RPM actually drops below where slippage will normally occur (usually somewhere below 6k rpm).
To me, the outer part of the drum looks suspicious. Maybe there was something going on there earlier that gradually affected the clutch behavior. Although then the plastic of the clutch cover would probably show signs of melting.

I guess the OP will soon have a new clutch/drum. He will be able to quickly eliminate one of the possible causes.
All in all, I guess he should also be asked if the bar and chain oiling is working properly.

I also was curious about the chain and bar itself, especially the groove. Begin with the saw off and a properly adjusted chain. Manually move the chain to see how freely it moves. I am looking for binding scenarios here. Next, take the chain off and look down the rails on both sides. Pics for us won't hurt here too.

He wrote that he also tried a new bar and chain. The sprocket, too.

 

[Sidecarflip]

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

Yepper...

Brake band is hanging up on the drum, obviously. Something is amiss under the side cover. Wonder if the OP has ever cleaned the swarf out of there? One thing I always do when I park any saw is I take off the side cover and clean out the accumulated swarf with a small paint brush and then use an air nozzle to blow out the remainder. Same applies in the field. I carry a small cheap HF paint brush in my pocket and clean the swarf from around the filler caps prior to refueling or refilling the bar oil tank. I've never had to replace a fuel filter or an oil strainer on ANY of my saws. Only takes a second to clean the swarf from around the filler caps and I always carry a sharp loop with me and when I see pitch starting to build on the heel of the saw teeth, I change out the chain and flip the bar over at the same time. When the second loop is starting to build pitch on the heel of the teeth, it's time to quit and have a beverage or something and/or quit for the day. Even my 45+ year old Stihl 028 has never received a new fuel or bar oil filter. I did replace the impulse line and fuel hose, one time, long ago and only genuine Stihl parts. I don't purchase off brand junk, especially not Chinese junk.

l always get a kick out of posters coming on here and posing questions and searching for answers when the obvious issue is staring them in the face. Why I don't comment much and just read the posts and that's it. I never have issues like that because if I do, I diagnose the issue myself and correct it myself. Echo makes a damn good saw, I have 3 of them plus the 3 Stihl's No Huskies however other than the pair of 308's I bought at an estate sales years ago. Got them both unfired packed in preservative btw and got them cheap too. They have dropped a lot of Whitetails over the years I might add, with handloaded in Norma brass 308 Cases with 168 grain Berger's and a good charge of H1000. They are not a long range rifle like my 338 Custom built 11-111 Savage Lapua or my Custom built Remington 700 action 300 Win Mag but for closer in work out to a couple hundred yards they are just peachy.

 

[Sidecarflip]

Probably running stale corn squeezed gas as well. All my saws only get canned gas and premium bar oil. I've ultrasonically cleaned many carbs for friends that have used corn squeezed gas in various power equipment where the gas phase separated and clogged up the passages in the carbs. Motorcycles sitting over winter seem to be prone to that issue. I own 4 bikes and every fall, the gas tanks get drained and I add a couple quarts of canned fuel to each one, start them and run them until warmed up and the shut them down, remove the batteries and the batteries go on tenders for the cold months. Preventive maintenance is key to me.

 

[chilipeppermaniac]

He wrote that he also tried a new bar and chain. The sprocket, too.

Yeah I saw that and posted such with a *****

Confirm status of Chain, Sprocket, Roller nose being free, ( Another member mentioned that he has experienced maybe 3 locked up noses)
*****I see that you installed new parts ( chain, sprocket, etc.

 

[chilipeppermaniac]

Probably running stale corn squeezed gas as well. All my saws only get canned gas and premium bar oil. I've ultrasonically cleaned many carbs for friends that have used corn squeezed gas in various power equipment where the gas phase separated and clogged up the passages in the carbs. Motorcycles sitting over winter seem to be prone to that issue. I own 4 bikes and every fall, the gas tanks get drained and I add a couple quarts of canned fuel to each one, start them and run them until warmed up and the shut them down, remove the batteries and the batteries go on tenders for the cold months. Preventive maintenance is key to me.

Sidecarflip,

I still remember the days in the 80's-early 90 ish when my 4 carb Honda Nighthawk would sit all winter. Pretty sure this was with old fashioned gas too.
I'd manually disassemble and clean the carbs each Spring.

 

[Old2stroke]

The problem is that we can't be sure from these posts whether the RPM actually drops below where slippage will normally occur (usually somewhere below 6k rpm).
To me, the outer part of the drum looks suspicious. Maybe there was something going on there earlier that gradually affected the clutch behavior. Although then the plastic of the clutch cover would probably show signs of melting.

I guess the OP will soon have a new clutch/drum. He will be able to quickly eliminate one of the possible causes.
All in all, I guess he should also be asked if the bar and chain oiling is working properly.



He wrote that he also tried a new bar and chain. The sprocket, too.

Slippage occurs just above idle and 1000rpm after it starts to grab, it should be locked up. If you stall the chain for whatever reason and keep the power on, the engine will sit somewhere in this slip zone. If springs get weak, the clutch will start to grab at a lower rpm than it should. The only thing that would make a clutch slip at high rpm would be shoes that are jammed on the spider and won't move out to full contact with the drum. Never seen it in 50 years of chainsaw repairs but things do happen.

 

[chilipeppermaniac]

Yepper...

Brake band is hanging up on the drum, obviously. Something is amiss under the side cover. Wonder if the OP has ever cleaned the swarf out of there? One thing I always do when I park any saw is I take off the side cover and clean out the accumulated swarf with a small paint brush and then use an air nozzle to blow out the remainder. Same applies in the field. I carry a small cheap HF paint brush in my pocket and clean the swarf from around the filler caps prior to refueling or refilling the bar oil tank. I've never had to replace a fuel filter or an oil strainer on ANY of my saws. Only takes a second to clean the swarf from around the filler caps and I always carry a sharp loop with me and when I see pitch starting to build on the heel of the saw teeth, I change out the chain and flip the bar over at the same time. When the second loop is starting to build pitch on the heel of the teeth, it's time to quit and have a beverage or something and/or quit for the day. Even my 45+ year old Stihl 028 has never received a new fuel or bar oil filter. I did replace the impulse line and fuel hose, one time, long ago and only genuine Stihl parts. I don't purchase off brand junk, especially not Chinese junk.

l always get a kick out of posters coming on here and posing questions and searching for answers when the obvious issue is staring them in the face. Why I don't comment much and just read the posts and that's it. I never have issues like that because if I do, I diagnose the issue myself and correct it myself. Echo makes a damn good saw, I have 3 of them plus the 3 Stihl's No Huskies however other than the pair of 308's I bought at an estate sales years ago. Got them both unfired packed in preservative btw and got them cheap too. They have dropped a lot of Whitetails over the years I might add, with handloaded in Norma brass 308 Cases with 168 grain Berger's and a good charge of H1000. They are not a long range rifle like my 338 Custom built 11-111 Savage Lapua or my Custom built Remington 700 action 300 Win Mag but for closer in work out to a couple hundred yards they are just peachy.

First off Sidecar, I want to express my well wishes for you with your health concerns. Second, your messages when you do choose to post are good food for us who are learning or trying to improve the health of our saws. I may be 60 now, but can always learn.

As for the OP and his Echo, He definitely is showing us the confirmation of the old adage, "It is so hard to diagnose by phone" or in our case, over the web without the actual saw in any of our hands.

I also wonder if his saw is out of warranty and if not, could he take it to the dealer? I am presuming he can't since he is posting here and replacing parts himself.

 

[altatim]

I wouldn't be surprised if its actually a lean failure caused by a poor H jet fueling. Not uncommon for a saw thats getting very lean to bog in the cut and cause the clutch to just slip against the drum if it doesn't have the rpm to keep pressure on the drum. I think chilipeppermaniac is onto something here... Try readjusting the carb settings for the H jet until it seems to be running way too rich and see what happens. Even too rich it won't get the rpms but it won't stall the same either.

 

[epo]

Slippage occurs just above idle and 1000rpm after it starts to grab, it should be locked up. If you stall the chain for whatever reason and keep the power on, the engine will sit somewhere in this slip zone. If springs get weak, the clutch will start to grab at a lower rpm than it should. The only thing that would make a clutch slip at high rpm would be shoes that are jammed on the spider and won't move out to full contact with the drum. Never seen it in 50 years of chainsaw repairs but things do happen.

You write about the situation when the engine/clutch is not loaded. It will take a higher RPM for the centrifugal force to be high enough to cause the clutch/drum set to exceed the (possible) engine torque.

 

[Old2stroke]

You write about the situation when the engine/clutch is not loaded. It will take a higher RPM for the centrifugal force to be high enough to cause the clutch/drum set to exceed the (possible) engine torque.

View attachment 1200953

No idea what you are trying to clarify. With your saw running at idle just below chain motion, put the chain brake on and give it some throttle. What rpm does it stall at?