Stihl 026 - Worm Gear / Clutch Spacer Washer Mystery?

[SteveSr]

Hello,

I recently picked up an 026 Pro off of Craigs List for our local trail club. Upon removing the clutch I immediately noticed the worm gear drive arm was rubbing on the top of the oil pump. I also noticed that there was no big spacer washer between the clutch and the worm gear.

I removed the worm gear and noticed definite melting and deformation of the plastic gear near the crank oil seal. Luckily it didn't get into the crankshaft seal. The worm gear did have the metal spacer washer behind it so that wasn't the reason. Staring at it some more and comparing my worm gear to some photos on the web it appeared that the bronze insert had moved inside the worm gear. To test this theory I put the worm gear in a small vise and was able to rather easily push the bronze bushing back into the nylon gear.

So my next question is how did the gear get pushed back into the bushing to begin with? Did it loosen up enough with heat such that other crud could push it in?

This brings up another question. Should this saw have the big clutch spacer washer installed? The washer would prevent clutch heat from getting to the worm gear and may prevent other crud from getting in there as well.

I have a 1999-04 and a 2004-07 IPL for this saw. The 1999 does NOT show the spacer washer whereas the 2004 shows a spacer washer. Anybody know why the spacer washer was added and what problem it solved? Should I put one back in this saw? Will it work with the existing clutch or was the clutch changed when the spacer washer was added?

Thanks,

Steve

 

[cedarshark]

Bump so someone can offer some help.

 

[SteveSr]

Bump so someone can offer some help.

I thought it was a little quiet in here! Where is the "Bump" button?

 

[KG441c]

Slack in oil pump gear?

 

[pioneerguy600]

Hello,

I recently picked up an 026 Pro off of Craigs List for our local trail club. Upon removing the clutch I immediately noticed the worm gear drive arm was rubbing on the top of the oil pump. I also noticed that there was no big spacer washer between the clutch and the worm gear.

I removed the worm gear and noticed definite melting and deformation of the plastic gear near the crank oil seal. Luckily it didn't get into the crankshaft seal. The worm gear did have the metal spacer washer behind it so that wasn't the reason. Staring at it some more and comparing my worm gear to some photos on the web it appeared that the bronze insert had moved inside the worm gear. To test this theory I put the worm gear in a small vise and was able to rather easily push the bronze bushing back into the nylon gear.

So my next question is how did the gear get pushed back into the bushing to begin with? Did it loosen up enough with heat such that other crud could push it in?

This brings up another question. Should this saw have the big clutch spacer washer installed? The washer would prevent clutch heat from getting to the worm gear and may prevent other crud from getting in there as well.

I have a 1999-04 and a 2004-07 IPL for this saw. The 1999 does NOT show the spacer washer whereas the 2004 shows a spacer washer. Anybody know why the spacer washer was added and what problem it solved? Should I put one back in this saw? Will it work with the existing clutch or was the clutch changed when the spacer washer was added?

Thanks,

Steve

I have read your post and can`t see where you mentioned if there was a small washer that sits down against the first step down in the crank just outside the seal on the oil pump side. That washer goes on first , the bushing you mentioned is a separate piece from the oil pump worm gear, it bottoms against the washer I mentioned, the worm gear and drive then slips inside the pump, turning the worm gear will facilitate it bottoming in against the washer. Next place the big cover washer that acts as a shield behind the clutch, then the clutch carrier threads on and tightens down against the step just behind the threaded portion on the crank stub. This big washer was added to help prevent a blown clutch from taking out the oil pump and hose , it may help with heat and keeping debris out but not what it was really intended for.
Parts numbers for the inner washer, 000 958 1234. The bushing, 000 993 0508. The big cover washer, 1121 162 1001.

 

[SteveSr]

I have read your post and can`t see where you mentioned if there was a small washer that sits down against the first step down in the crank just outside the seal on the oil pump side. That washer goes on first , the bushing you mentioned is a separate piece from the oil pump worm gear, it bottoms against the washer I mentioned, the worm gear and drive then slips inside the pump, turning the worm gear will facilitate it bottoming in against the washer. Next place the big cover washer that acts as a shield behind the clutch, then the clutch carrier threads on and tightens down against the step just behind the threaded portion on the crank stub. This big washer was added to help prevent a blown clutch from taking out the oil pump and hose , it may help with heat and keeping debris out but not what it was really intended for.
Parts numbers for the inner washer, 000 958 1234. The bushing, 000 993 0508. The big cover washer, 1121 162 1001.

The inner washer (spacer) was present. The big cover washer was absent. Sounds like I need to add one on reassembly and clean up the worm gear with a knife.

I find it hard to imagine that one of those clutches would spontaneously disassemble itself but that big washer and the clutch drum should keep everything contained.

Thanks,

Steve

 

[Al-Stihl]

Wonder if it was really a pro model or if it just had the stickers and is really a standard model that was converted?

 

[cedarshark]

Does it have an adjustable oiler and decomp ?

 

[pioneerguy600]

The inner washer (spacer) was present. The big cover washer was absent. Sounds like I need to add one on reassembly and clean up the worm gear with a knife.

I find it hard to imagine that one of those clutches would spontaneously disassemble itself but that big washer and the clutch drum should keep everything contained.

Thanks,

Steve

I have seen quite a few clutches grenade, more often one or more of the springs will break off on one end and continue to flail for several hundred more revolutions before breaking off the opposite end, a lot of damage occurs almost instantaneously to the oiler and the delivery line if just one spring breaks off. The clutch carrier spider arms are prone to metal fatigue after a saw reaches very high hours of operation, especially if the saw chain if jammed a lot or run real dull, seen many clutch spider arms break off, big time mess after that.

 

[Rockjock]

Steve from my IPL it shows that for the 026 pro and non pro that the washer is in place. NOW I do recall on a saw I had, a 026 that the washer was missing and it caused the worm gear to bind up. I had one from a 024 and it worked just fine.

all the 026 IPLs I have list the washer as needed. Good luck.

 

[splitpost]

before you go adding a washer (part id no.7 )you need to see what clutch you have,the clutches use two different retainers and spiders ,I have added a picture showing the difference the parts I am refering to are 4 and 5 if you have the clutch with the retainers that look like 5 no washer is needed,i also have 2 026 saws apart on my bench and both are 44mm,both have decomps and run the same clutch(using retainer no.5) but only one has the adjustable oiler,both these saws are stock and never been touched,hope this clears it up for you

 

[SteveSr]

Does it have an adjustable oiler and decomp ?

Yes, it really is the Pro model. It has the adjustable oiler, decompression valve and compensating carb. It also has the lever latch (like the 260s) air box cover which doesn't appear to fit very well. I thought it might have been replaced but I see a picture of this style in my 1999 printed IPL.

 

[SteveSr]

before you go adding a washer (part id no.7 )you need to see what clutch you have,the clutches use two different retainers and spiders ,I have added a picture showing the difference the parts I am refering to are 4 and 5 if you have the clutch with the retainers that look like 5 no washer is needed,i also have 2 026 saws apart on my bench and both are 44mm,both have decomps and run the same clutch(using retainer no.5) but only one has the adjustable oiler,both these saws are stock and never been touched,hope this clears it up for you
View attachment 363261

Thanks for the clutch explanation and pictures! I do indeed have the clutch meant for use WITHOUT a spacer washer. So apparently it was like it was intended from the factory. That still doesn't explain the boogered worm gear. So what is the issue with adding a spacer washer to this clutch? Will it interfere with the clutch shoes? There appears to be about zero clearance when the clutch back side is laid on a flat surface. I thought I remembered the spacer washer being dished slightly to take this into account but maybe not enough.

 

[SteveSr]

I had a chance to take apart a 260 with the spacer washer behind the clutch and compared it to the other clutch. The clutch shoes appear to be identical. There is a minor difference in the clutch spider. The one without the spacer washer is about .030" thicker through the crankshaft section. Guess how thick the spacer washer is? About .030"! So in order to fit a washer on the back side of the clutch one would have to mill off .030" from the removal nut on the outside of the clutch. I think I'll pass!