# Which usually wears out first, the clutch or the drum?



## quercus_kelloggii (Dec 7, 2010)

Which usually wears out first, the clutch or the drum?

I bought a Homelite XL (UT-10655) 16" off CraigsList for $35.  The guy said it needed some help.  It starts and runs.  I cleaned it up, filed the bar a tad, flipped it, chain looks good and sharp, added bar oil, replaced the pull rope and fired it up and tested, adjusted the idle.  It does well on the small stuff (4" or so) but the bigger oak (6" +) it'll keep revving but the chain will stop if I put a lot of pressure on it.  So I took it apart today, took off the clutch drum to check out the clutch.  The clutch and drum have some gunk on them, maybe thickened grease or something, not entirely sure.  Will clean that out and see how it does.  Maybe get a new drum at some point, hence my question...do the drums wear out first and the clutches keep going or ?  How does one tell exactly?  Do the clutches have anything on the contact surface like brake material, or is it metal to metal contact?

I've attached a photo of the clutch (gunk visible top side) and the drum (same).

Any info appreciated.

Also, since I don't have the special tool to remove the clutch, and I tried a punch and peen to see if I could relatively gently knock it loose, what is the best way to remove the clutch (and do I really have to worry about a needle rollers of the clutch bearing??).

More pics / details here: http://www.sierranature.com/temp/homelite.html












Thanks for any info/help!


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## smokinj (Dec 8, 2010)

I would replace both at the same time, but your question its the clutch!


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## 727sunset (Dec 9, 2010)

Clutches are designed to outlast drums but they also can be abused. All that debris you showed will wipe off. Saw clutches are generally all metal and do not have pads. On the clutch surface and drum interior look for signs of wear, blue heat marks or chunks missing. Your clutch will likely be installed on a left hand thread. It can be removed carefully with a drift punch or sometimes tools aren't that difficult to make. If you see anything amiss with the drum they are not expensive. Get a new one c/w bearing. Hope this gets you started, we're here if you need more help.


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## quercus_kelloggii (Dec 9, 2010)

Thanks for the replies.  I cleaned it all up and gave it another test.  Still the same.  Did a compression check (albeit with my tester, i can't turn it all the way in or it will hit the piston) but I get a meek 60 PSI which would make the way this saw cuts make sense.  Not sure if turning it all the way in would get much more PSI but it seems to hold the reading.

What are my options with this?  Ring job do it or ??  I don't want to sink much money into the saw but I like it and all this is a learning experience.

727 - thanks for the detailed info, I'm learning!  Appreciated.


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## smokinj (Dec 9, 2010)

quercus_kelloggii said:
			
		

> Thanks for the replies. I cleaned it all up and gave it another test. Still the same. Did a compression check (albeit with my tester, i can't turn it all the way in or it will hit the piston) but I get a meek 60 PSI which would make the way this saw cuts make sense. Not sure if turning it all the way in would get much more PSI but it seems to hold the reading.
> 
> What are my options with this? Ring job do it or ?? I don't want to sink much money into the saw but I like it and all this is a learning experience.
> 
> 727 - thanks for the detailed info, I'm learning! Appreciated.



Pull the muffler and get some pic's of the cylinder wall.


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## quercus_kelloggii (Dec 9, 2010)

smokinjay said:
			
		

> Pull the muffler and get some pic's of the cylinder wall.



Ok, will do, I'll get that up within a day or two.  Appreciated!


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## 727sunset (Dec 9, 2010)

qk ~ 60 PSI compression is not good news and often insufficient for starting. These saws are small, lightweight and a real joy to use but do not come with high output. I know mine will not allow downward pressure during the cut or else the chain will stall. The fact that yours is running the same makes me think there's not much wrong. Nice score! 
Before considering an engine rebuild maybe retest with a known good pressure gauge?


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## quercus_kelloggii (Dec 9, 2010)

727sunset said:
			
		

> qk ~ 60 PSI compression is not good news and often insufficient for starting. These saws are small, lightweight and a real joy to use but do not come with high output. I know mine will not allow downward pressure during the cut or else the chain will stall. The fact that yours is running the same makes me think there's not much wrong. Nice score!
> Before considering an engine rebuild maybe retest with a known good pressure gauge?



Well it starts really well and easy.  It cuts little stuff (< 3" or so) really really well.  Tried to cut some ~ 6" oak and pine and it is a chore.  Will do it but takes awhile and lots of chain stalls.  Oiler seems to be working, chain throws some good chips.  Almost seemed like it does better using the top portion of the bar too.

I haven't used a lot of saws, my 55cc slices through things super easy, but I thought this XL might be a nice limber/small stuff saw (8" or so rounds) and backup saw.  Right now, "limber" is about it.

Don't have access to another compression tester at the moment, but I'll try some teflon tape on the threads of the one I have, see if that makes any difference.


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## CTYank (Dec 9, 2010)

quercus_kelloggii said:
			
		

> 727sunset said:
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Generally, compression leaks result in hard-starting. So you have a good sign there. Compression testing on tiny (chainsaw) engines really requires a suitable tester, because the volume of the hose interior is so large compared to that of the combustion chamber.

I'd scrub the entire area of the clutch. That is one awesome mess.

Re R&R of clutch, a manual I have says "first separate engine from engine housing as outlined in ...." That sounds a bit much. I'd try to pull it in place.

They note the old trick of stuffing rope in the spark plug hole to serve as a piston stop. And that clutch drum nut and hub have left-hand threads. Clutch tool is Homelite p/n A-24060.

Also, good idea to remove recoil starter, so as to not twist things apart while you REPLACE ENTIRE CLUTCH. Just suggesting. Best wishes.


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## quercus_kelloggii (Dec 9, 2010)

CTYank said:
			
		

> Generally, compression leaks result in hard-starting. So you have a good sign there. Compression testing on tiny (chainsaw) engines really requires a suitable tester, because the volume of the hose interior is so large compared to that of the combustion chamber.
> 
> *I'd scrub the entire area of the clutch. That is one awesome mess.*
> 
> ...



I cleaned it up, still not sure how to tell if it is worn out or not.  Interesting note on the 'suitable tester', the one I have is for autos, does that make a diff?


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## Beowulf (Dec 9, 2010)

I use the same compression tester for cars, bikes, saws, etc.  You do need to have a schrader valve (check valve like a car valve stem uses) in the hose, so that it will keep the pressure in the hose as you crank the engine.  It takes a few pulls to hit max pressure that the saw is capable of, since the hose volume on the tester must be "pumped up" with the small piston/combustion chamber.  No schrader valve, and the pressure just bounces up and down with the piston movement.  With a schrader valve, the compression will build as you crank the saw, until it hits it's peak and won't go higher.

I think you may not be getting a good reading if you cannot thread the tester in tight; the teflon tape is a good idea.  I do not think your saw would start with 60 psi max compression.  I think you need something over 100 psi to run.  My little 020 recently tested at 175 psi.

You might try a little brake cleaner on the clutch; also make sure that the weights will move.  If one is stuck, the clutch will not grab with much force.

The needle bearing is important, but if it is not shot, pack it full of wheel bearing grease and wipe off the excess.  The drum should spin smoothly with the engine stopped, no roughness or slop.

Good luck!  You're off on a learning adventure...


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## 727sunset (Dec 9, 2010)

qk ~ Your clutch looks fine in the photo. I see the "OFF" rotation is indicated. Drum is OK as well. The spur on the other side is somewhat worn but you can keep cutting for a bit with a used chain. Check and make sure raker depth is not more than .020" or it'll cause chain grabbing as well.
"Suitable tester" refers to shorter the better. As CTY pointed out the volume of air in the long automotive hose tester is a factor when trying to compress it with small displacement engines.
The Homelite displacement is apx half of your 55cc saw...works great for pruning and limbing. If you have to cut say larger than 4" try rocking the bar so the chain is not cutting the full log diameter. 
Let us know how it goes.


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## smokinj (Dec 9, 2010)

Long story short no bluing is a great sign. I have seen 880 clutches look like you dip them in liquid blue crayons.


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## Danno77 (Dec 9, 2010)

for fun, scuff the metal in the drum and on the clutch with some sandpaper. won't make a difference long term, but should really grab the first couple of time's you use the saw.


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## quercus_kelloggii (Dec 9, 2010)

727sunset said:
			
		

> Your clutch looks fine in the photo.


Thanks, nice to hear.



			
				727sunset said:
			
		

> Check and make sure raker depth is not more than .020" or it'll cause chain grabbing as well.


This may be an issue, I will take a photo of the chain and look into measuring the raker depth, they did look very shallow to me.



			
				Beowulf said:
			
		

> I think you may not be getting a good reading if you cannot thread the tester in tight; the teflon tape is a good idea.


Will try the teflon tape and see if that helps today if I get some time. Is there a big different in doing it cold vs. 'normal operating temperature'?  I didn't get a different reading either way before. Guess if the cold reading changes w/ the teflon tape addition and go from there.



			
				Beowulf said:
			
		

> You might try a little brake cleaner on the clutch; also make sure that the weights will move.  If one is stuck, the clutch will not grab with much force.


I used paint thinner to degrease.  Good idea on making sure the weights will move, didn't do that.



			
				Beowulf said:
			
		

> The drum should spin smoothly with the engine stopped, no roughness or slop.


There is actually some slop (side to side movement) with the drum, maybe the bearing are shot? in it? Spins smoothly but there is slop.  Maybe investing 12 bucks for a new drum would be worth it anyway?



			
				Danno77 said:
			
		

> for fun, scuff the metal in the drum and on the clutch with some sandpaper. won't make a difference long term, but should really grab the first couple of time's you use the saw.


My dad actually suggested this to me, but I forgot about it.  

Thanks all!  Very helpful and appreciated.


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## quercus_kelloggii (Dec 9, 2010)

Tried Teflon tape on the compression tester and it was better, but still not very good at 90 PSI.  Maybe a different tester (if I had access to one) would read higher even.  Not near the 115-145 PSI the service manual states, but at this point unless I get a known good tester I am not going to rely heavily on the 90 PSI reading.

I did take the muffler off since it was so easy to do so, and took some pictures.  Hard to get a good picture but I put a series of images up here:

http://www.sierranature.com/temp/homelite-cylinder.html

here's a smaller image:






Yet to tear it apart again and check the clutch weights to ensure they move... and yet to check the chain rakers...


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## Beowulf (Dec 10, 2010)

Piston/Cyl don't look bad in my opinion, at least.  The fact that the engine keeps running at speed while the chain stops should keep you focused on the clutch for a little more of your diagnostic energy.

Have fun!


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## quercus_kelloggii (Dec 10, 2010)

Thanks for the input Beowulf.

I'll check out the clutch more tomorrow if I have time.  Probably try and get a new spur sprocket too since this one has side to side play.

Meanwhile, thought I'd put some chain and bar tip images up to see if this is normal.  The chain rakers look way lower than my other saw chains, and the chain raises up on the bar tip sprocket, it isn't flat against the bar, is this normal?

Thoughts on the chain and bar tip?  Chain is an Oregon 91 which seems to be right for this saw/bar.

As always thanks all!


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## 727sunset (Dec 10, 2010)

Once again qk everything looks good. 
The rakers look fine and the sprocket is supposed to keep the chain off the bar.
You're in good shape


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## smokinj (Dec 10, 2010)

quercus_kelloggii said:
			
		

> Tried Teflon tape on the compression tester and it was better, but still not very good at 90 PSI. Maybe a different tester (if I had access to one) would read higher even. Not near the 115-145 PSI the service manual states, but at this point unless I get a known good tester I am not going to rely heavily on the 90 PSI reading.
> 
> I did take the muffler off since it was so easy to do so, and took some pictures. Hard to get a good picture but I put a series of images up here:
> 
> ...




I would say your compression test something is wrong there. The way the saw was running still sounds like its in the clutch after seeing these picks. Or the saw is way out of tune. How hard is the pull when starting the saw?


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## quercus_kelloggii (Dec 10, 2010)

smokinjay said:
			
		

> I would say your compression test something is wrong there. The way the saw was running still sounds like its in the clutch after seeing these picks. Or the saw is way out of tune. How hard is the pull when starting the saw?



I will take another look at the clutch soon as I can.  The saw pulls really easy, can feel a little resistance (the only saw I can compare it to is 55cc, don't have another smaller saw to know what a smaller saw should pull like - next time I'm at my dad's I'll try his Stihl ms170 and see what that pulls like to compare).

I'll tear it apart and check out the clutch again.  The spur sprocket/drum has play so maybe I'll replace that too.  But I'll look more at the clutch.  Make sure the weights all move, maybe sand it down a tad and/or get some brake cleaner and try that (although I would think the paint thinner was okay for degreasing).  Thought too, I could cover the clutch surface w/ a black sharpie pen and try the saw, take it back apart and see if there are any areas not making contact.  Maybe?

Anyway, next thing I'm going to do is look at the clutch again.  Stay tuned (please)! and thank you very much for everyone's help.


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## smokinj (Dec 10, 2010)

quercus_kelloggii said:
			
		

> smokinjay said:
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I cant see that saw only having 60psi with the look of things and started. stranger things have happen though!


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## quercus_kelloggii (Dec 10, 2010)

smokinjay said:
			
		

> I cant see that saw only having 60psi with the look of things and started. stranger things have happen though!



Well I got it up to 90PSI with some teflon tape on the tester threads...


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## smokinj (Dec 10, 2010)

quercus_kelloggii said:
			
		

> smokinjay said:
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90 still way to low to run. Strange things can happen though.


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## quercus_kelloggii (Dec 14, 2010)

Update: took the saw apart again to check out the clutch.  Since it was recently cleaned, I could easily see uneven wear on the clutch shoes.

Pictures (each photo is a different "shoe"):

The areas outlined in red are not making contact with the drum.














I also noted earlier that the drum has some side-to-side wiggle play.  There are two washers on each side, I think putting a thicker washer on the outside (spur) side would allow the nut to tighten it all together more and lessen the play?  Not sure if this would help with the contact issue but an easy thing to try.  Are the stock washers hardened? ETA: (Not sure this idea is logical, as the drum will have to spin freely and I can't lock it up, so not sure what the answer is.)

Thoughts appreciated.


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## ProfessorGT (Dec 16, 2010)

First you need to determine if a lack of power (most probably), or a lack of chutch holding ability (not likely) is your issue. When the chain grabs and stops moving, what does the engine do? 

(If the chain was too agressive it could take too big a bite for the engine size, but from the looks of the pics you posted on the chain, it doesn't look like this is your issue.)

If the engine just doesn't have enough power that's one thing, but that could just be because of the state of tune. Have you tried adjusting the carburetor? The high speed needle could be off and therefore severely limiting power.

What happens if you throttle up fully BEFORE beginning your cut? Does it bog down quickly and stall the chain (not the engine) as you begin to cut? Does it only stall the chain when you bear down into the cut? The chain should be sharpened properly so that you do not have to bear down when cutting, but it should allow just the weight of the saw itself to basically make the cut on it's own, with you only having to guide the saw.

I didn't see your cylinder pics, but if there is no severe scoring I doubt that this is the issue. Again I go back to the state of tune. I'd try some carb adjusting, and make sure fuel delivery is not a problem. Make sure the clunk in the tank, and the line to the carb are in good shape and are clear, and are not partially blocked nor pinched. If so, then try asdjusting the high speed needle to see if this gives you more power. If it behaves eratically to the adjustments the carb might need overhauling (due to fuel deposits or trash in the system). This could be causing issues with the carb diaphram also, which will definintely effect power output. If you've never done this before search around online and you will find overhaul info and some good step-by-step guides to help you through it. Just get your carb model number and brand, and you'll find everything you need.

From the looks of it your clutch did get hot (blue coloration indicates overheating - due to slipping) but that is most probably due to the slippage incurred from when the chain stalls and you continue to feed it fuel while the chain is still stalled. Again, my guess is that the issue all boils down to lack of power due to an inadequate state of tune. I'd try to wake it up first by starting with the carb and the fuel delivery system. Heck, I've found brandy-spankin-new Walbro and Zama carbs (complete!) for my 31cc weed whacker engines on ebay for less than $10.00!

Good luck!


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## smokinj (Dec 16, 2010)

quercus_kelloggii said:
			
		

> Update: took the saw apart again to check out the clutch. Since it was recently cleaned, I could easily see uneven wear on the clutch shoes.
> 
> Pictures (each photo is a different "shoe"):
> 
> ...






I still think its the clutch but as stated before it could be way out of tune as well. Just to make sure Lean it up a little see if it will pull any better through the cut if it doesn't help its the clutch.


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## quercus_kelloggii (Dec 16, 2010)

Ok guys, thanks very much for the feedback.   I recently got all set to get a new ring and just try that (but I'm getting frustrated trying to figure out what ring is the right ring), but now I'll try messing with the carb settings to tune it.

Found this http://store.chainsawr.com/blogs/tu...djustment-and-tuning-of-a-chainsaw-carburetor and will try that first and see where that gets me.  Also ProfessorGT - I will do some test cuts to see how the saw is performing at the different stages like you suggest.

Greatly appreciated you guys.


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## amateur cutter (Dec 16, 2010)

I've got one of those little saws as well, the clutch looks fine to me. Shoe contact is not always 100% surface contact. Try the tuning & sharpen the chain, keep in mind that it's a very small saw & will stall pretty easily if you "lean" on it. Mine has since new. Also check the oil output & make sure the chain turns freely by hand. I've had mine get fussy with crud between the sprocket & bar. A C


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## Danno77 (Dec 16, 2010)

amateur cutter said:
			
		

> I've got one of those little saws as well, the clutch looks fine to me. Shoe contact is not always 100% surface contact.


I'm with AC on this one. Besides, you may think the contact isn't being made in those places, but given the direction of the spin, One might assume that contact is being made INITIALLY on the front of each of those shoes and by the time the whole shoe engages there isn't any/much slipping, which is causing what you see as wear in the front and non-wear in the rear. Doesn't mean the rear isn't touching, just means that the rear isn't sliding against the drum.


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## smokinj (Dec 16, 2010)

Danno77 said:
			
		

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I agree with all of that tune it and you should know for sure what up.  

http://web.archive.org/web/20051018212959/www.madsens1.com/sawtune.htm


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## quercus_kelloggii (Dec 21, 2010)

Well I "tuned" the carb the best I could and it didn't get much better.  The engine seems to bog down, almost like it is too rich(?), when I let the saw weight carry the saw through 5-6" stuff.  Bogs down and the chain stops.  Without a load it would rev to what I think was 4 cycle sound.  Acceleration was good, maybe a tad boggy at first.

I'm going to take the carb off and apart and clean it out, maybe it really is a fuel issue.  

After some test cutting, the saw would cut out on me.  I tried tuning it some more and now it is way off base   I got tired of pulling the starter rope so much.

I'll pull the carb and clean it out the best I can, check the parts (diaphragm etc) and see where that takes me.  Probably couldn't hurt.

Also need to pick up a 5/32 file and hit the chain up, but I think that is a secondary issue if at all.

I'll post again when I get the carb apart.

Thx.


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## southbound (Dec 22, 2010)

Did you buy this saw new??? Why I want to know is so many this can happen to a saw in it's lifetime...

I would try to replace the clutch springs with the correct ones,I'm not saying the ones in there are wrong but they may be..If so they may be to strong and not letting the clutch out properly....

The piston seems to have some carbon build up..Need to be careful you lock it up,, What mix oil you use?? what ratio???  The carb needs to be set right...

I would lose that safety chain as well.. It looks dull in your pic's and they will over work a saw....


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## southbound (Dec 22, 2010)

Check your pm's!

Also if I missed it what does the plug look like and is it the right plug... When I bought my 038 it had the wrong plug and once hot and under load it would act like yours....


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## quercus_kelloggii (Dec 22, 2010)

southbound.  Picked the saw up off CL used.  I used Arnold all ratio oil (http://media.mydoitbest.com/imagerequest.aspx?sku=760545&size=2&warehouse=C&newsize=200).  The saw is supposed to run 32:1.  I have no idea how it was treated before me.  The cylinder and piston do not look bad from what I know, but I have some new literature to check out on that now/soon.  

The plug is correct I believe being a DJ7Y and gaped appropriately at .025, and it looks ok.  I have it in mind to pick up a new plug anyway next chance I get however.

I found this off another site, and it is supposedly from a Stihl carb manual, and makes a lot of sense.  Maybe I'm going up a rope of sand, feels that way sometimes, but figure it can't hurt to look at the carb more.  I don't think it is the clutch or the chain, but I am a newbie and have thought I should just take it in to have someone look at it but I can't afford that.  I thankfully have another saw that is good running and will chew through almost anything, this saw was hopefully going to be a backup/limber/small stuff saw.  Right now it is a limber at best.  I want more out of it if I can pull that off, well, time will tell.



> Condition = Engine Speed drops quickly Under Load - Low Power.
> 
> Cause = Air Filter Plugged.
> 
> ...



I will definitely sharpen the chain, not in the budget (there is no budget, or very very little) to get a new one I don't think.

The carb, well that needs set/tuned now for sure (I should have counted the turns out from seating from the get go, lesson learned.).

Thanks for your time and thoughts, they are appreciated for sure.


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## Mainely Saws (Dec 23, 2010)

I would also make sure that the muffler is not partially glogged from years of use with a heavy oil . You can use a good quality 50:1 mix in that saw ( todays oils are much better than when the saw was new ) .


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