STIHL 045AV clutch question, I'm stumped.

[Supercharged86]

Dear Friends, I just acquired a good running Electronic 045AV with chain brake. The clutch drum is one that I've never seen before and I'm at a loss at how it's supposed to work. When It's running, even at idle, the clutch is continuously fully engaged and I'm not sure why. Do I have a broken clutch mechanism or am I missing something? I see that the center toothed sprocket piece moves in and out, I don't know if this is normal. Thank you in advance. Steve

 

[cbfarmall]

What does the chainbrake look like? Stihl made a decoupling brake for some of their saws that not only had a drum brake, it also had a mechanism that would decouple the shoes from the clutch hub, letting it freewheel. My 031 didn't look anything like that one and I don't know if the 045 was ever sold with that option. Personally, I'd get rid of that clutch in favor of a standard one.

 

[Supercharged86]

What does the chainbrake look like? Stihl made a decoupling brake for some of their saws that not only had a drum brake, it also had a mechanism that would decouple the shoes from the clutch hub, letting it freewheel. My 031 didn't look anything like that one and I don't know if the 045 was ever sold with that option. Personally, I'd get rid of that clutch in favor of a standard one.

I don't know if this crummy picture shows definitively which type it is. Thanks.

 

[cbfarmall]

That seems to be the standard factory chainbrake for the 045. My ipl doesn't show a decoupling style was ever an option on the 045, only the 031. Maybe the clutch was from some other application. Does the center piece moving in and out affect its operation? It sure doesn't resemble the 031 clutch.

I stand by my earlier statement--just swap in a standard 045 or 056 clutch. As many of those saws have been killed by failed ignitions, you will have no problem.

Edit: after review, I see some bits in that chainbrake cover for the isolating clutch. Clean it and you may see mechanisms other than those for the band.

 

[cbfarmall]

Did some searching, found this:

https://chainsawr.com/products/stihl-056-chainsaw-isolating-clutch-assembly-1115-160-2001-new-s-os

You will need to find an older version of the 045 or 056 IPL to see what all parts are involved. Newer electronic IPLs seem to omit these obscure bits. My copy of an owner's manual has a reference to this clutch but provides zero details.

Leave it to Stihl to make something simple so complicated.

 

[cbfarmall]

To answer your original question of the clutch being constantly engaged, unless there is a bind between the drum and clutch, I'd put fault on the spring. With the engine off, can you easily pull the chain around the bar or is the clutch still engaged? It should still act like a normal clutch. Complex as it is, it's hard to say what's wrong over the internet.

 

[stihltech]

You need to find an old tech that actually worked on these. With maybe 40 years experience?

 

[Supercharged86]

Thank you my friend. It only freewheels if the sprocket part is in.

 

[cbfarmall]

I would think, then, it would have a spring to hold it out and the cover mechanism would push it in when the brake is tripped. Does the cover operate this way as well.

You'll have to disassemble to find out why drum won't stop turning. I'd say you're looking for typical clutch/drum issues and nothing particularly related to the isolating clutch.

 

[stihltech]

Spring only lasted 55 years?
As stated above, swap it for a solid center clutch. Then you can get parts.

 

[Supercharged86]

Thanks guys. Appreciate the help.

 

[cbfarmall]

Put a regular clutch and cover on the 045 and sell the isolating clutch kit to a collector. You never know with that stuff.

 

[stihltech]

The operation is this- there is a flat spring with fingers that keeps the round plate engaged with the center spline. To disengage- the ramps in the sprocket cover push the round plate in to disengage when the brake arm is actuated along with the band.
The cure in the day was to put a second flat spring behind the plate to increase pressure. I don't thing the spring was available since the early 80s. Same with the clutch shoe spring. There is also a special tool that engages the center spline to remove it.
Cure, as stated, replace with a solid center clutch.
Sometimes you just need an old guy around.

 

[Supercharged86]

The operation is this- there is a flat spring with fingers that keeps the round plate engaged with the center spline. To disengage- the ramps in the sprocket cover push the round plate in to disengage when the brake arm is actuated along with the band.
The cure in the day was to put a second flat spring behind the plate to increase pressure. I don't thing the spring was available since the early 80s. Same with the clutch shoe spring. There is also a special tool that engages the center spline to remove it.
Cure, as stated, replace with a solid center clutch.
Sometimes you just need an old guy around.

Thank you my friend. I'm looking into that option. I wonder if I'll also need a non-brake clutch cover?

 

[stihltech]

No. If I remember right, the you only need to change the clutch. I don't remember taking the cover all apart.

 

[Supercharged86]

No. If I remember right, the you only need to change the clutch. I don't remember taking the cover all apart.