My first project saw! (no pics yet) -- a free 034 AV

[maple1]

I always though AV was Anti-Vibe, and Magnum was magnesium cases.

But I don't know if that's right or not...

 

[DexterDay]

There were older saws that were Magnums. The 038 Mag was one.

But yeah, The 044/440 up to the 088/880 are all Magnums. Its been told that the sticker ads 10% more torque

As for the AV. A lot of older saws had AV on them. That's when Stihl was starting to go from there old style saws, to the newer gen. AV stands for Anti Vibe. The 031AV, 024AV, 028AV, 034AV, etc.. Now, with the even newer gen saws, the AV has disappeared, as all saws (Stihl) have an AV system of one type or the other. Some are still better than others and I would prefer all my saws to ride on springs. But the 441, and 361/362 are the only bigger saws to do so currently.

 

[DexterDay]

I always though AV was Anti-Vibe, and Magnum was magnesium cases.

But I don't know if that's right or not...

Lots of other saws use Magnesium cases, but that may be right? All Pro saws use mag cases, so the 260/261, 362, etc should have it too.

I just know 1 thing..... The sticker makes my 460 go faster

 

[MasterMech]

OK what does the "AV" stand for?

And another question. You se 046 or 460 "magnums" and 044 "magnums" and so on what does the magnum mean? Does every saw over a certain size say it? I personally cant say i have seen an 044 with out magnum written on it?

The Magnum designation was meaningful on a handful of saws. It was the biggest, the baddest version of that model. 038, and the 056 are two that come to mind. The 056 Magnum II is a prized collector item and a 91cc heavyweight powerhouse. As far as the newer 044/440 type saws go, it's just a sticker.

Plenty of non-Magnum saws that have magnesium cases. Quite a lot of them actually.

 

[smokinj]

Av anti vibe. Mag well if it don't say it you don't have it....

 

[Jon1270]

So I'm back from vacation and had a few minutes to play with my free saw. I pulled the cover off the carb/air cleaner area, and was surprised to find that I could spin the flywheel backwards about a quarter turn with my fingertips. It moved quite freely within a 90-degree or so range. So then I pulled the cylinder cover off and removed the spark plug. No obvious damage there -- piston moves up and down around the top of its cycle as the flywheel is rotated, but comes to a sudden stop at either end. Top of piston looks fine, and the plug seems a bit sooty, which I would not expect if it had been running lean and seized.

I figured the next step is to pull the muffler so that I might get a better look inside the cylinder and at the exhaust side of the piston. The 20" bar with its full-comp chisel chain is starting to get in the way, though, so I remove the bar nuts and the side cover and lay the sharp, pointy bits off to the side. Intending to turn my attention back to the muffler, I flip the saw upright and hear a little clunk, of something like a nut or screw hitting the carrying case on which I am working. I lift the saw out of the way, and quickly find a small hard plastic part a bit over an inch long -- apparently a chain guide of some sort. It's got a keyhole-shaped projection on the back, so it quickly becomes obvious where it came from. Hardly daring to hope, I give the starter rope a tug and it draws easily, a satisfying FwopFwopFwopFwopFwop noise coming from the still-open spark plug hole.

So, the saw isn't seized at all; it was just jammed by its own chain guide. It's not running yet (apparently been sitting with gas in it for a couple of years) but I don't think this is going to be a big project. With the plug back in I can just lift the saw by the starter rope, so compression seems decent. I'm almost disappointed. Almost.

 

[maple1]

Wonder where that came from? Did it fall out the recoil side? If so, that would certainly jam the flywheel up. Then ya gotta wonder how it got in there.

 

[Jon1270]

Wonder where that came from?

You can see the keyhole-shaped hole it attaches to in the pic above, just at the tip of my middle finger, above the front bar stud. Seems like a friction fit that just got loose.

 

[maple1]

I was thinking where did it fall out of the saw from.

Unless it fell out of the recoil housing, I'm not sure how it could stop the engine from turning over - then I'd wonder how it got inside the recoil housing. Stranger things have happened though.

 

[Jon1270]

Oh, I see what you're asking. I was wondering the same thing, but unfortunately I didn't see where it came from so I can't answer this conclusively. There is plenty of room under the front cover for the loose guide to find its way over into the recoil, though.

 

[maple1]

Hope it runs for you now - that would be a nice surprise.

I had almost the same thing happen here with a gas drill. Found a stray screw up against the flywheel - it came from the recoil housing. So ya never know.

 

[Jon1270]

I've made myself tired trying to start the saw, and it's not firing at all. I switched to fresh gas and the spark looks great, so this is looking like a fuel delivery problem. Carb kit, I'm guessing. The fuel line looks good. Any thoughts from those who've done this before? The only carbs I've ever overhauled were on old Japanese motorcycles.

 

[DexterDay]

Id put new fuel line, fuel filter, and impulse line. I have had some Nasty saws and not one has needed a kit. Likely the impulse line is cracked and no fuel gets delivered. Or crack in fuel line..

Sounds like it aint gonna cost you much. Well worthy of a Giant You Suck!!

Congrats. I may have a fuel line for it and possibly the impulse. Have to look when I get home. I have about 30 fuel filters. Give you a really good deal on it.

 

[Jon1270]

Thanks, Dexter. I'm going out but I'll check back later. There are a few other parts I'm going to have to chase down too: an oil cap (original is damaged and leaking), a scrench with a Torx end, a plastic latch for the case (missing one) and a 20" scabbard. Oh, and one of the Torx muffler bolts has been replaced with a standard hex bolt, so it would be nice to get that back to original. Otherwise it looks awfully good.

 

[maple1]

I think I would do a leak-down test on it.

 

[clemsonfor]

Yea all new fuel lines. And yea that is a plastic guide that keeps chain running true. Its that type plastic that is real slick. Its prokly fine. The Carb kits can be had on eBay for less than $10. There easy. I think like 2 rubber diaphragms is all.

 

[Jon1270]

Well dang, I was completely wrong. Couldn't find any cracks in the fuel or impulse lines. I disassembled the carb and found it very clean inside. Put it back together and pulled the rope several times with the air filter off, and gas started dribbling out the back of the carb, ergo it's probably not a fuel delivery problem. So, I pulled the muffler off and found the exhaust side of the piston badly scored, the rings almost indistinguishable from their grooves. It'll be a new piston and rings at least; maybe the cylinder too. I don't have a long T27 wrench to pull the cylinder and get a better look, so I'll start by ordering one.

FWIW, the old gas I drained out of it was suspiciously colorless. I'm wondering whether the previous owner didn't grab the wrong gas can.

 

[DexterDay]

If your gonna go aftermarket and want a Good kit thats priced right? PM me. There is good aftermarket and Chi com aftermarket garbage. .

Also, I would do a pressure or vacuum test after rebuild. Because if the scoring is exhaust side and below the port, then an air leak is likely. Seals will come with the aftermarket kit too..

 

[Jon1270]

Will do, Dexter. Fortunately I have a pressure tester and some associated manifolds.

 

[MasterMech]

Also, I would do a pressure or vacuum test after rebuild.​

Do it before as well. Unless you are going to replace everything, and even if you are, knowing what the problem is before you tear it down is valuable knowledge when ironing out the inevitable kinks after you get it running again.

Wow, cylinder kits for these saws are quite inexpensive! (broken link removed to http://www.ebay.com/itm/CYLINDER-AND-PISTON-KIT-Aftermarket-Fits-STIHL-034-MS340-48mm-w-o-decompression-/140610208962?pt=LH_DefaultDomain_0&hash=item20bd0584c2#ht_780wt_735), not bad. That's also a 48mm kit that would upgrade that 034 to 036 specs. I've used a couple kits from this seller now (that's how I know they are Hyway brand kits) and have been happy with both of them.

 

[Jon1270]

I would do a pressure or vacuum test after rebuild.

Do it before as well

My torx wrench arrived today, so it was time to dig deeper into my saw's problems. I busted out my recently acquired tool kit, sealed off the exhaust, replaced the carburetor with the appropriate manifold, and did my first-ever pressure test. The saw held no air whatsoever. I could hear air escaping every time I squeezed the bulb, so it didn't take long to figure out that the clutch-side crank seal was leaking like a sieve. After pulling the clutch and getting the oil pump gear out of the way, I sprayed the seal with oil and used the pressure-test bulb to blow bubbles.

I went ahead and pulled the cylinder. The piston is evenly scored from top to bottom. all the way around, and the top ring is broken. The cylinder doesn't look so hot either, so it'll be a complete top end replacement. Time to go shopping...

How do you gauge the acceptable amount of play at the connecting rod / crankshaft? There's a bit of slop there, and since this is my first time taking one of these apart, I have no idea whether it's a problem.

 

[Jon1270]

Wow, cylinder kits for these saws are quite inexpensive! (broken link removed to http://www.ebay.com/itm/CYLINDER-AND-PISTON-KIT-Aftermarket-Fits-STIHL-034-MS340-48mm-w-o-decompression-/140610208962?pt=LH_DefaultDomain_0&hash=item20bd0584c2#ht_780wt_735), not bad.

Are you sure that's a Hyway kit? I don't see the brand mentioned anywhere.

 

[MasterMech]

Are you sure that's a Hyway kit? I don't see the brand mentioned anywhere.

That seller is particularly responsive if you call/email him questions. Both kits that I have ordered from him were Hyways.

 

[Jon1270]

Thanks, I'll drop him a note and see what he says.

 

[Jon1270]

Also, how much sense would it make to split the case and replace all the gaskets and seals, since I've already got the thing halfway apart? Is replacing just the crankshaft seals likely to be sufficient?