Clutch Sticking

[dolmarjay]

Hi (newbie here),

Hoping some may be able to help. I have a 'Dolmar 109' which was working fine until the other day when I noticed the chain would not spin freely when the engine was off, when I try spinning the chain (engine off) it is turning the engine or when I try to start it the chain spins...So I'm assuming the clutch is sticking ???

1. If this is the case how do I remove the clutch to inspect it or can I tell the clutch is sticking without removing it ?
2. Now for the stupid question... Is the clutch what I see when I have the side cover off, the 'round thingy' that has the sprocket behind it ? (if this has confussed anyone I can try an post a picture !)
3. Is it easy to replace the sprocket on this model ?

One other question, unrealated to this problem, just more for interest sake, is it normal for a chainsaw to leak bar oil when not being used ?

Any help or advice would be very much appreciated.

Thanks...

 

[ozflea]

Sounds as if one or all the springs have let go or maybe a bit of sawdust is caught between the clutch shoes and the drum.

A lot of saws dribble oil when sat down after cutting it's the warm oil in the galleries leaking out under gravity.

McBob.

 

[dolmarjay]

Sounds as if one or all the springs have let go or maybe a bit of sawdust is caught between the clutch shoes and the drum.

A lot of saws dribble oil when sat down after cutting it's the warm oil in the galleries leaking out under gravity.

McBob.

Thanks for the quick reply ! May I just ask, are the clutch shoes waht I can see after I have removed the side cover ?

 

[upandcommer]

your clutch shoes are just like the shoes on a drum break held in place by springs once the centripetal force overpowers the springs the shoes will engage the out hub (drum) and spin the chain. You have one of two problems the springs have become broken or fatigued to the point of not pulling the shoes off the inner wall of the drum and or something has gotten lodged in between the shoes and the inner part of the drum thus the drum is always engaged. Some clutches are easy to remove just find the right size socket my mac is 3/4 pull the muffler off the saw insert some good stiff 1/2 rope into the muffler hole while the saw is at bottom dead center and loosen to the right (reverse thread). On the other hand some of the saws out there require specialized clutch removal tools and any dealer worth his salt should have most of the said tools for deconstruction to either dislodge the sawdust and or replace the springs on the clutch for you.

 

[daemon2525]

Here is a picture of an external clutch. Notice how there is a gap between the internal (heavy) parts and the external drum.

The external drum should turn freely of the internal parts.

The spring (only one on this saw) , or springs (on other saws), should pull the internal parts in towards the middle away from the drum when the engine is not running.

Centrifugal force of the engine spinning causes the internal parts to expand, catching hold of the drum.

Sorry that this seems technical, I have always wanted to say those big words.:hmm3grin2orange: :hmm3grin2orange:

 

[daemon2525]

Sorry UpandCommer, It took me a long time to find the picture and post. I did not see your reply. Very good explaination.

 

[dolmarjay]

Here is a picture of an external clutch. Notice how there is a gap between the internal (heavy) parts and the external drum.

The external drum should turn freely of the internal parts.

The spring (only one on this saw) , or springs (on other saws), should pull the internal parts in towards the middle away from the drum when the engine is not running.

Centrifugal force of the engine spinning causes the internal parts to expand, catching hold of the drum.

Sorry that this seems technical, I have always wanted to say those big words.:hmm3grin2orange: :hmm3grin2orange:
QUOTE]

Thanks for the photo, that makes it easy to see what I'm trying to explain. So can I take the clutch apart without removing it ? My clutch seem similar top this photo as in I don't have a nut holding the clutch on. Therefore to remove it would I need to spin the whole clutch off... Meaning does the clutch just thread onto the shaft ?

 

[dolmarjay]

your clutch shoes are just like the shoes on a drum break held in place by springs once the centripetal force overpowers the springs the shoes will engage the out hub (drum) and spin the chain. You have one of two problems the springs have become broken or fatigued to the point of not pulling the shoes off the inner wall of the drum and or something has gotten lodged in between the shoes and the inner part of the drum thus the drum is always engaged. Some clutches are easy to remove just find the right size socket my mac is 3/4 pull the muffler off the saw insert some good stiff 1/2 rope into the muffler hole while the saw is at bottom dead center and loosen to the right (reverse thread). On the other hand some of the saws out there require specialized clutch removal tools and any dealer worth his salt should have most of the said tools for deconstruction to either dislodge the sawdust and or replace the springs on the clutch for you.

I don't seem to have springs as such, but more like 'leaf springs' if that makes sense... So the 'drum' should spin indepent of the shoes ??? If there is just something caught in there if I remove it the shoes should move away from the drum... is that right ?

 

[daemon2525]

Yup.... Except it will be reverse thread. (others correct me Quick if I am wrong) You will have to stop the machine from turning over while you do this, as UpandCommer has explained.

I just noticed myself that this saw has no nut holding it on. That is somewhat unusual. Notice how this particular saw has little places for a tool
to grab the clutch. They are the notches (or whatever) just close to the inside (crankshaft)

 

[dolmarjay]

daemon2525, upandcommer, ozflea

Thankyou for your replies.... I will take your valuable information back to the 'shed' and see what I can figure out.
I will post back with my results... give me a couple of days though !
THANKYOU, once again for your time....

 

[daemon2525]

I can't imagine what you mean by leaf springs. Everything I have seen has some sort of coil springs. Maybe yours should have springs and they just "vaporized" LOL!!!

 

[Lawn Masters]

I think I know what you mean. leaf springs like those on a truck. I've seen those before on I believe some Husky saws.

 

[dolmarjay]

I can't imagine what you mean by leaf springs. Everything I have seen has some sort of coil springs. Maybe yours should have springs and they just "vaporized" LOL!!!

I thought you might say that...Yeh, it was the best way I could describe it. Hmmm maybe they have vaporized !!.... I'll try and post a pic which will give a better description. But I can't seem to see any 'coils' type springs. It's more like... nope I can't explain it, I'll post a pic !

 

[RaisedByWolves]

Ive seen this before when the clutch bearing is pooched. The chain is usually jerky when you pull it if this is the case.

 

[dolmarjay]

Ive seen this before when the clutch bearing is pooched. The chain is usually jerky when you pull it if this is the case.

Could you expand on this... because now that you mentioned it, when I used to spin the chain on the bar there seemed to be a spot that would grab/stick. Is that what you mean ? Now if I try and spin the chain it has resistance all time from the engine turning over.

 

[RaisedByWolves]

Sometimes when the bearing goes the needle rollers will bunch up and stick it (clutchbell) to the crankshaft. When this happens the sprocket is now off center and the chain will bind then go slack (or not) when you turn it.


Then just for kicks it will rotate fine (evenly) but still turn the engine or the symptom will dissapear alltogether.


Either way you are still best to disassemble the works and inspect everything.


Let us know what you find.

 

[dolmarjay]

Yep... Will do !

Thanks

 

[dolmarjay]

Fixed it...

There was some 'gunk' which had got in behind one of the clutch shoes and was causing the shoe rub on the base of the drum (not the outer edge). I sprayed some carb cleaner in behind the shoes to soften the build-up and then used a bent feeler gauge to get in behind and around the shoes and clean all the 'gunk' out... Ta daa !!! The drum spins.

I did try to remove the clutch just to inspect the sproket but I was unable to, I tried to 'tap' it to spin it off the tread, but it didn't really move so I left it. Therefore, to remove it will I need a special tool ? And which way does it thread 'off' - turn right or left ?

I have inserted a photo to help describe the 'leaf spring' description earlier, however when I look at it, it looks nothing like leaf springs !!! I took the pic first up, so... as you can it hadn't been cleaned :blush: :blush:

 

[Renoracing]

interesting Dolmarjay, i wnat to remove my clutch on my 109 but never do that before. Anyone can help us!!!

 

[dolmarjay]

I'm going to try and make up a tool to do the job, I'll post back if I have any success ????