Something seems wrong with chainsaw (clutch)

[mcdougy]

So, I've made a few comments lately on how great my Dolmar ps6100 has worked flawlessly for the last 5 years or so.
Today something seems to be happening with the clutch is my best guess.
I was doing a few things that I typically don't do with my saw today when I think the problem has appeared. It was a bit warmer outside temp than I typically use my saw AND I was noodling some pieces of white oak.
The saw was working perfectly fine for darn near a tank of fuel. While noodling, all of a sudden the saw pretty much locked up and stalled. (Unusual behaviour) I thought I had heard the rpms start to ramp up slightly, which is typically the sign I'm running out of fuel, so I decided that maybe it was simply out of gas and locked up with a hard stall due to noodling.
I went and filled it with gas and it was not completely empty.
Upon re starting after the refuel, the chain was spinning at idle (which was not usual) It seemed to be normal idle rpm. I then engaged the chain break and it stalled out again. I did 2 or 3 retarts and the same behavior continued. Starts easily, but chain spinning when at low idle, engage chain bake, hard stop and stall.
I removed the cover to look at the outboard clutch and I'm not familiar enough to know if I see anything wrong. I definetly did not come across any broken parts that I know of.
I will attach a picture and can any of you folks tell me what my next steps should be? As to what could be going on with my saw.
Thanks for the help

 

[EbS-P]

Is the clutch free to spin when the saw is off???
would a broken clutch spring do it?

 

[mcdougy]

Is the clutch free to spin when the saw is off???
would a broken clutch spring do it?

With the saw off, turning the clutch,turns the saw engine over.

 

[mcdougy]

Once I remove the circ clip and gear, is there any advice on how to get the clutch cover off easily to inspect the springs?

 

[Newbie78]

That's an inboard clutch. The clutch is inboard of the chain/sprocket.

That's not a clutch cover you're talking about, that's a clutch drum. You already have the clutch cover off...

The clutch drum should slip off effortlessly as long as the brake band is not engaged.

Likely you overheated the clutch and perhaps, as has been suggested, broke a spring and the shoe(s) is jammed cockeyed in the drum somehow..

Do you run your saw full throttle, or do spend time at part throttle? Part throttle operation, especially under heavy load (like full-bar ripping cuts) will cause clutch slippage and overheating.

The brake-band appears to be loose in the pics. Is it? If not, that'll be the first thing.

Oh, and that's not a gear, that's a sprocket. A rim sprocket.

 

[mcdougy]

That's an inboard clutch. The clutch is inboard of the chain/spocket.

That's not a clutch cover you're talking about, that's a clutch drum. You already have the clutch cover off...

The clutch drum should slip off effortlessly as long as the brake band is not engaged.

Likely you overheated the clutch and perhaps, as has been suggested, broke a spring and the shoe(s) is jammed cockeyed in the drum somehow..

Do you run your saw full throttle, or do spend time at part throttle? Part throttle operation, especially under heavy load (like full-bar ripping cuts) will cause clutch slippage and overheating.

The brake-band appears to be loose in the pics. Is it? If not, that'll be the first thing.

Yes...your terminology is much better than mine. Thank you.
There is a bearing and gear attached to the drum. This is what I'm guessing is making it hard to remove.
The brake band Is all in one piece and appears to be working fine. Loose when not engaged, tight when brake on.
I would say that I was running the saw at w.o.t 90% of the time.

 

[Newbie78]

Perhaps you seized a clutch bearing. Quite unusual. I don't know where the bearing is in that diagram. Wth! But you know where it is.

I'd grab that clutch drum with some biggish slip-joint pliers and give it a bit of a tug. Careful of the crank-end. You don't want to gouge it or mess it up in any way. If you have big enough pliers, you should be able to grab it end-wise by the splined part of the clutch drum, rock it a bit back and forth lightly, and yank it off. Probably.

PS, that saw is CLEAN! Holy crap!

If that won't get the clutch drum off, I (me, maybe not you) would probably put the bar and chain back on, rev it up, and engage the chain brake. That might smarten the thing up. Just give it a good brake once, then take it apart again.

 

[mcdougy]

Perhaps you seized a clutch bearing. Quite unusual. I don't know where the bearing is in that diagram. Wth! But you know where it is.

I'd grab that clutch drum with some biggish slip-joint pliers and give it a bit of a tug. Careful of the crank-end. You don't want to gouge it or mess it up in any way. If you have big enough pliers, you should be able to grab it end-wise by the splined part of the clutch drum, rock it a bit back and forth lightly, and yank it off. Probably.

PS, that saw is CLEAN! Holy crap!

If that won't get the clutch drum off, I (me, maybe not you) would probably put the bar and chain back on, rev it up, and engage the chain brake. That might smarten the groan up.

The bearing is inside the 7 cog gear and around the crank shaft.

 

[mcdougy]

I will get another pic when I return home. If I need a bearing puller it is sure going to be tough to get under the drum due to small clearances.

 

[Newbie78]

The bearing is inside the 7 cog gear and around the crank shaft.

i know. It is a separate part, called a clutch bearing. It should just be slipped inside the clutch drum hole. The clutch drum should just slip off with it or without it. Usually, you have to be a bit careful you don't drop the bearing in grubby stuff, cause it can fall out all over the place. Not the needles in the bearing, the whole, caged bearing.

There's not a puller I'm aware of that will pull that drum. It's not meant to be pulled. It should just slip right off of there holding it with a couple of fingers.

I don't know why the bearing is not exploded in the "exploded diagram".

 

[mcdougy]

 

[mcdougy]

I can't even get a wiggle out of it with pliers and hand muscle.

 

[Newbie78]

Huh.

Maybe spray some wd40 in there and tap it lightly with a hammer and leave it for a while. I don't know this regarding that saw, but the "hole" in the end of the crank might be a grease point and lead to the clutch bearing. Spray something in there too. Don't tap on the crank, tap on the clutch drum.

Some husky's have that hole as a grease point so..idk, maybe a dolmar does too. Pretty sure my dolmars don't.

I once had a frozen threaded adjuster rod that went through a cast piece on a farm implement. Over the course of a month or more I sprayed wd and tapped and farted around every time I thought about it. One day I went to it with a wrench and it spun like nothing was ever wrong. It is about a 2" adjustor on a 1" course threaded rod. Anyway, not saying you have a lot of time but.

A little heat might help too. But you don't want to go nuts with the heat. Just heat the clutch drum around the centre.

 

[Newbie78]

You said it went lean without running out of gas. While you are farting around, pull the muffler and have a look at the piston. Just for shits and giggles.

 

[Newbie78]

Is that another clip under the splined part of the drum? Is that a two piece drum or something? Edit; duh, that's a pressed-in splined hub

There appears to be some rust in places there shouldn't be..or maybe I am seeing things.

Could be the pic, is there damage to the clutch drum. It looks broken? Or almost broken?

 

[Newbie78]

There's likely a way to use a small three-hook puller on that, but you're not there yet..

 

[mcdougy]

 

[mcdougy]

With a consistent effort and vice grips on the sprocket I was able to get it off.
The clutch plate was wedged against the drum.
Broken spring was revealed.
Should I get a entire assembly or try to find just the spring?
The clutch assembly looks to be around $50 canadian, a spring is like 6$.

 

[mcdougy]

No rust, and hub appears to be fine as well.

 

[mcdougy]

For the record....do you like my work bench ???

 

[blades]

That's not a work bench I can still see the top

 

[ericm979]

I'd get a whole clutch. Also clean the inside of the drum. If it's worn, replace that too.

The clutch is reverse threaded on the crank. Use a length of clean small diameter rope in the combustion chamber to keep the crank from turning while you loosen the clutch. It looks like that clutch will need a special tool to loosen it.

 

[Newbie78]

Get the special tool. Give it a few burps with an impact gun. It will probably spin right off. Reverse thread as already noted. Leave the spark plug in, of course

Normally no rope is required...

 

[mcdougy]

Get the special tool. Give it a few burps with an impact gun. It will probably spin right off. Reverse thread as already noted. Leave the spark plug in, of course

Normally no rope is required...

Special is not available from what i can see....as in not in stock....unable to order

 

[ericm979]

I think there are or were Makita saws that were similar or the same as many Dolmars. Maybe a clutch tool for one of those will work.

You can try the drift method as shown here:

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But don't use his method of keeping the crank from turning! That's likely to break a fin off the fan. And for god's sake don't use a chisel on the clutch. Use a soft metal drift like a brass rod. The rope in the combustion chamber is safer for the rod bearings. And in this case there is nothing for an impact gun to work with, unless maybe the tool has a hex on it. Make sure the piston is covering all the ports before you stuff the rope in the plug hole.