Stihl 440 spitting dust and smoking...

[Blinky]

My #1 saw, it's always started and worked like a champ. S couple of weeks ago someone was using it, when the chain derailed. Whoever put the chain back on put it on the OUTSIDE of the sprocket instead of ON the sprocket.

A little later I fired it up and it it revved way higher than normal a few seconds and died... it would not restart for more than a couple of seconds. Last cut of the day, we needed a sharp chain and this was the only one so we decided to put the chain and bar on a different head... that's when I noticed the chain being off the sprocket. We put it on right and finished up, it started up fine but it still didn't sound exactly right to me.

I've used it several times since and the sound always kind of bugged me in the back of my mind but I never really thought it was anything. Yesterday I was felling an 18" sweetgum and it was really struggling, especially in the backcut... nothing but dust and lots of blue smoke; when I pulled it from the unfinished cut the chain was drooping 3/8" from the bar... I had to finish the cut with a 200T (the chain retightened when it cooled off). Right before this I had touched up the chain and it was making nice curly chips when bucking.

I can operate a saw and take care of the chain but my knowledge stops there. I don't understand why it can cut through a horizontal log fine and then start spitting dust when I make a backcut. I'm wondering if the drive links and/or sprocket are messed up from that 'chain off the sprocket' incident. (The chain is a Stihl 33-RSC-72) Maybe the blue smoke was normal because the saw was working so hard but it seemed like too much to me and that has me wondering about the clutch.

I took it to a shop this AM and they said there was nothing wrong with it but the mechanic never actually looked at it, just the shop owner who is really a hardware dealer, not a mech.

Anybody got some ideas? I'm about to go out and buck down the rest of that sweetgum so maybe I'll have more to add later. I'm grateful for any help.

 

[tek9tim]

Do you make 45 degree backcuts like the people we were trashing on in another thread recently? That's about the only way I can think of that a backcut could be different from a bucking cut. If so, I've had chains that cut tolerably well in straight cut situations, but are too dull to make the sloping cut of my face worth a darn.

The blue smoke is most likely a direct cause of the bar/chain getting too hot. This here is a great example of why east coasters talk smack about west coast dogs. The only way you can put enough pressure on the bar to get it that hot is by using your dogs. (The main problem with the logic in the smack talk is that you don't put that much pressure on the bar when you're using dogs properly, and it saves you a ton of effort)

 

[daemon2525]

You've probably trashed the spline on your clutch drum while running the chain on it.

Maybe the sprocket rides in a good part of the spline while in bucking position and on a bad spot during the backcut.

I would not see how could not have a bad clutch by now.

 

[Blinky]

Thank you guys, the weather's been lousy here so I've only done some bucking with it so far and it seems to be fine until the chain heats up... which is about 2/3rds of the way through an 18" sweetgum. Once it's hot and smoking I can back off for 5 or 10 secs and it goes back to cutting fine.

Why would it go from making chips to making dust and then back to making chips again a few seconds later?

BTW, I generally do horizontal backcuts and occaisionally plunge them on leaners... I never really even thought about doing a 45 deg. backcut... what situation calls for it?

Also, I have both inside and outside dogs on this saw and use them... but mainly as a pivot point, not to press the bar through the cut. I like the saw to do most of the work, that's why I started this thread, I was having to put a lot more pressure on the bar to get through the backcut... like the blade was trashed or something.

I'm going to inspect the spline tomorrow AM, that sounds like it could be what the problem is, that, and/or the clutch.

Thanks again.

 

[stihl 440]

45deg backcut

Don't do a 45 deg backcut, stupid people do it. They think it makes the tree go the right way, but it don't. The tree thinks you are sawing a bigger notch in it and will go the way the bigger notch is sawed. Keep doing the horizontal backcut and boring, it is the proper way to do it. The situation that calls for it, is when you want it to swing right around and kill you. Or kick back and do the same thing. And for suggestions on the saw is maybe a bent bar or dull chain. Look at the bar from the front toward the power head it should be straight as an arrow, if not than it is bent. Dust sounds like a dull chain.

 

[Highside]

could well be the spline, however what condition is the bar in? the chain could be tipping in the rails as you get into the backcut.
you guys talk about bucking...what is that? nothing I've ever heard of down under!

 

[RED-85-Z51]

could well be the spline, however what condition is the bar in? the chain could be tipping in the rails as you get into the backcut.
you guys talk about bucking...what is that? nothing I've ever heard of down under!

Limb removal after felling a tree, and cutting the tree into managable sections.

 

[RaisedByWolves]

No,no, thats limbing......




Bucking is cutting the trunk into manageable pieces.:newbie:







Sorry, its new and I just had to use it......

 

[RED-85-Z51]

Well, I had The managable sections part...But Ive always heard it used "bucking the limbs off"

No,no, thats limbing......




Bucking is cutting the trunk into manageable pieces.:newbie:







Sorry, its new and I just had to use it......

 

[5555555]

It sounds like your oiler's not working. Your chain and bar aren't supposed to smoke. Maybe the problem with your backcut is just a result of you bar and chain heating through the face cuts and finally overheating on the backcut. I'd check the oiler.

Jim

 

[turnkey4099]

It sounds like your oiler's not working. Your chain and bar aren't supposed to smoke. Maybe the problem with your backcut is just a result of you bar and chain heating through the face cuts and finally overheating on the backcut. I'd check the oiler.

Jim

I second that. I had much the same problem. After two trips to the dealer, we found that on the bench it would oil some but in the cut not. Took a new pump to cure it.

The only times I have had with hot chain/smoke has always been dull chain first, not enough oil second.

Harry K

 

[Blinky]

could well be the spline, however what condition is the bar in? the chain could be tipping in the rails as you get into the backcut.
you guys talk about bucking...what is that? nothing I've ever heard of down under!

Can you elaborate on what tipping the rails is? I checked and dressed the bar after the first smoking incident; it's straight as far as I can tell and wearing evenly. I cleaned the oil ports and flipped it over just for good measure.

The oiler is adjusted wide open and it doesn't put out as much oil as I expected it to... I figured it could be the cold weather slowing it down. When I point the bar at say, a cinder block it takes about 5 - 10 seconds before enough oil builds up to make an easily noticable dark streak.

I'm reasonably good with a wrench, should I try replacing the pump myself?

 

[Highside]

When you are using a bar that is getting on a bit, and your chain is getting down as well-ie the drive links are worn- the chain can tilt to one side in the rails, and won't cut.It will behave like a real blunt chain, smoke and dust. I don't really think that is your prob,but it may be worth trying a new bar/chain. Also check that you don't have a section of chain that is bent.
Maybe the oiler,but a chain will still cut without oil(obviously only until it gets rigor-mortis or until you blow your tip!) I will be interested to hear about the condition of the drive spline

 

[sugarbush]

pull your clutch and check the wire attached to the worm gear that operates the oiler, the wire may be broke or slipping.

 

[rxe]

Is the sprocket damaged after the, er, chain fitting incident? Before I knew much about saws, I had a little Stihl 009 that I would carefully set the chain tension on, and then go out cutting. At random intervals, it would go slow and smoke and the chain appeared to be incredibly tight. So I loosen it...then suddenly the chan was so loose it fell off the bar.

The sprocket was damanged - so that sometimes the chain was on tight, sometimes loose. Is there anything like that going on in your bar/chain combo? Nicks in the chain tangs or something similar?

 

[Highside]

how did that spline look?

 

[Blinky]

OK, so I finally got this figured out, you guys were instrumental for sure.

The splines on the driveshaft have some minor rounding on the tips, probably caused by the misfit chain incident... the drive links on the chain were in much worse shape. It took close inspection in good light to see how they were bent and most had flattened tips... like they were peened.

Switching chains cured the problem... I don't know why I didn't do that right off, I had a spare in toolbox the whole time. I still don't get why cutting horizontally was such a problem while vertically it cut OK. The spare chain worked better even though needed sharpening... once I touched it up... yeah baby! That's the way I remebered my saw going through wood.

The bottom line is, if somebody needs a saw, they can use my 029, the 440 is hands-off from now on, same with my new 200T.

Thanks for helping out.

 

[RiverRat2]

Ditto on the lack of chain Lube!!!!

I second that. I had much the same problem. After two trips to the dealer, we found that on the bench it would oil some but in the cut not. Took a new pump to cure it.

The only times I have had with hot chain/smoke has always been dull chain first, not enough oil second.

Harry K

Souns like it is oiling some,,,,,But not enuff

Oh I see you got it when is the last time you changed the Sprocket, Is it a rim sproket set up???? if you change chains you really need to consider changing the sprocket, Get the rim sprocket set up, if you dont already have it,,,,It will save you money on chains and a new rim sproket is only about 5 bucks VS the clutch cover style Sprocket