Well it looks like I bought myself an extra bevel gear head. On Saturday I put the replacement head on and that didn't change much. It had a S/N just 99 off from the one on my machine. They all make the same sound when not driven by the engine - just one of the many things I have to learn adapting to the Stihl clearing saw ecosystem, as Husqy bevel gear heads are dead quiet.
I also think I might now know why there are two different Part #s for these heads - Stihl is in the process of replacing heads on all of their shaft-driven devices with sealed unit heads - no more nut to take off to add grease. My dealer even has a tube of this grease but these new heads just can't be greased. This feels strange to me, but that's the new deal.
The new head makes less of a screech as the blade spins, and has been staying at exactly the same point on the shaft rather than slipping down.
Yesterday, I thought I was back to Square One with this machine. Still wobbled like a drunken sailor and occasionally made the entire shaft and the entire machine vibrate and shake, sometimes violently. The dealer suggested "sometimes you might just want to let the machine break and call in the Warranty." I was hesitant to do that - I need a machine I can count on for the next 7 weeks on remote sites. I need to hire a 3rd person in October to get back on schedule - I need to be able to count on $1400 machines, not wonder which week they will go back to the shop.
It has mostly just been my misfortune that the only person I have access to in Michigan that has ever run one of these (the Stihl rep) had to go out-of-state for a week of meetings. So I requested some attempt to sort this out via a new gear head. Since that didn't work, I will probably step up and buy the extra one, not a terrible thing to have with a clearing saw, believe me. The dealer would file it as a warranty claim but I don't want to do that.
I ran a couple tanks through the saw yesterday (Saturday). To maintain the continuity on that particular job, I continued along the existing cut edge but this meant cutting small diameter (1-2") Scotch Pine all day; it is a Scotch Pine removal job. The saw cut these perfectly fine, but the wobble was ever present. Though without putting it in big wood I didn't see too much of the heavy vibration. That morning the dealer continued to suggest that I "just wasn't used to the anti-vibe" and every time I heard that sentence I would cringe and think - are they crazy? You mean the Vibration System? What "Anti" - vibe? But I was working from a negative - how much vibration would there be without those bumpers?
Today I went over to another job, which had all diameters and a diverse species mix to cut. I had to get it done anyway. I started out with the 560 but was reaching the conclusion I would just have to give it back to the dealer for the Stihl people to sort out; I have to get up to my far away jobs pronto to stay on (behind, now) schedule and get my new hire working. I would have to bend over a whole lot and just run a chainsaw for a while and come back for this saw later.
The saw was doing the vibration of the whole shaft even when building RPMs on the way into a larger cut, before the cut even started. I still felt there was no way this machine would last a week of daily use like this.
But I ran out the first tank, sharpened, and re-filled. The wobble got worse. It was even affecting my ability to operate the saw in that it would lead the saw head into places that I didn't want it to go, leading to kickback. That's not dangerous on a brush saw if you are clipped into the harness, but if you hit something big that is hard on the clutch. Hanging 23 lbs off a free-swinging clip on the harness is a unique way to cut things. I maneuver a clearing saw very carefully for quality cuts and now the wobble was interfering with that some.
It seemed to be bad whenever I attempted to take-off from Idle, and the saw was having more and more trouble taking-off at all. Finally I realized - this brand new saw with it's automatically adjusted carb was losing power.
EUREKA!
One of my Canadian contacts had told me to delete the muffler screen immediately. I didn't do that, figuring when it came time to clean it I would decide then. Technically I have to have a spark screen on my equipment on Federal contracts. I was hoping I could run with the screen on. And I just wasn't thinking about the idea much while the depression of possibly wasting $1400 just gnawed at me. I hadn't even run a gallon of gas through this saw (1st qt was Motomix then 91 Octane + HP Ultra). On all of the Husqvarna saws I have run in my life, I only have to clean the muffler screen annually, and even then sometimes the wire brush just doesn't accomplish much as they haven't carboned up that much.
I looked in the muffler and could no longer see any brass at all on the screen, even with a flashlight! Black as night in there.
So I started taking the saw apart. It looked like the screen was only removable by splitting the muffler - I have had a saw like that before. I got the muffler off but couldn't figure out how to split it open. Finally I caved and opened the manual. This part I couldn't believe - it suggests taking the saw to a dealer for muffler maintenance! Is Stihl always like this? I'm not really digging the Stihl experience very much so far at all.
I keep looking at it and it looked like the depressed area leading to the screen in the center of the muffler might hold a wrench, and it did - I could have just removed the screen with the scrench supplied with the saw. Doh! But then the user manual doesn't tell you this either, nor divulge a suggested cleaning schedule for the screen. The Canadian suggested it would have to be done daily if I left it in there.
The screen was a surprising design. I hate it. It looked somewhat like this (image cribbed from eBay, it won't be around forever):
The whole thing was solid black, no light showing through well at all. I couldn't see how I could ever get the whole thing very clean. I have a small wire brush about the diameter of a dime in my saw toolbox, but even that wouldn't fit in the cup shaped screen. I could only clean the outside of it.
I doubt I will ever put it back in the saw. I will watch closely near dark one day next week when someone else runs it. I have never run a saw without the screen, never needed to. I wish there was an after-market flat screen that just fit in the nut that screws out of the muffler, that could be cleaned quickly and easily. But I seriously doubt one exists.
But now - I HAVE A BRAND NEW SAW. This thing is a beast. It cuts Pine like a hot knife through butter. If I create a bit of kickback and the saw kicks into a non-target stem, it simply slices right through it rather than stopping.
There is still a wobble feel, though it is not as dramatic. And now it makes sense. The anti-vibe system picks up all it can, but there is a limit. The shaking of the shaft is gone until you hit the very top end at the far edge of a big stem. The motor isn't gasping for air and running funky and shaking all the time.
My Husqys still run noticeably smoother and I am starting to see this is the limit of what the Stihl design can accomplish. I doubt Stihl would have ever told me to try taking the screen out. I still hope to pick up some other copy of this machine and see if mine just might not have something seated correctly. Some day. I won't buy another copy of this saw without running another one first, that is for sure, and will evaluate the Husqy 555 Fx in a few weeks.
But this thing cuts, and cuts, and cuts. And that is what I paid for.
I have really been wondering now - how does the Magic-Tronic system account for increasing carbon on the screen? How could it? On a fuel injected vehicle, there is a sensor that measures the air-flow, at least on the way into the cylinders, and of course an O2 sensor on the exhaust. I don't think M-Tronic can adjust for an increasingly dirty screen. And for a solid black screen on less than a gallon of gas, I just, I dunno. Go figure. Or something.
