New Stihl toys, New carb adjustment tools?

[WildnCrazyGuy]

Sorry. I did a bit of searching, but not much found. I haven't purchased new Stihl toys in a while, probably 5 years now, and when I do, I see things I've never seen before. I have no need to tinker with these yet, but curious what I have. I purchased a new FS130 and BR600 Magnum. They seem to run ok, probably not up to full power yet because the trimmer has only about 3 tanks through and I just finished the dealer's "filled up" tank of gas. (Maybe 1/3 full, more like 1/4)

I didn't even get to look at them much, but peeked in the carb area this morning out of curiosity. Are these the NON adjustable carbs, or just need new tools to adjust now? Looks like a hex key or something. I liked the little orange screwdrivers... got 2 more with these purchases. I guess they're good for the idle adjustment. Manual says some carbs are autotuned now. Makes me think that's what I've got with these. Thanks.
View attachment 309077View attachment 309078

 

[XSKIER]

Did you search outside of the chainsaw forum? Although hard to comprehend, there is a world outside of AS chainsaw forums when it comes to OPE. I too spend many many hours here fueling CAD, BAD, and TAD.

fs 90r weed trimmer
http://www.arboristsite.com/showthread.php?t=235387

 

[xtremez]

They're adjustable. Those are tamper resistant. Takes a different tool to adjust the settings. Looks like it just uses an Allen wrench

 

[dswensen]

Looks like it just uses an Allen wrench

Not so sure. Hard to tell, but are two of the flats on the "Allen head" longer than the other four? Would make sense that they would choose a shape that isn't easily reproducable from a standard allen wrench set modified with a grinder

EDIT: Thinking about this a bit more, I guess the shape of two flats longer than the other four WOULD be reproducible from a standard allen wrench and a grinder.

EDIT x2: This is one of those visual puzzles isn't it? (Is it an old woman's profile, or a young woman's profile?) I don't think it's an allen head-type recess, I think it's a "tit" sticking out that has six sides, yes?

 

[naturelover]

Looks more like a small bolt head than a Allen key to me.....


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[WildnCrazyGuy]

Again I searched, but only found one or two things talking about the new tool for the Stihl carbs. I found a part number that is supposed to be the latest hex carb tool for Stihl carbs. Took that to my dealer, and one is on order. Fingers crossed the Stihl Special Police don't lurke here on a daily basis. :msp_tongue:

 

[WildnCrazyGuy]

SHHHHHHHHHHHHHHHhhhhhhhhhhhhhhhhhhhhhhhhhhhh. Hope this helps someone like me who was trying to figure out what is needed for these screws. I found somewhere else online that a 3 or 4mm hex nut adapter might work depending upon the brand. I'm guessing the thinness of the tool makes a difference in order to be able to get into it. But the right tool is shown below.

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[XSKIER]

Very nice!

 

[Swamp Man]

you can adjust them with a 4mm nut driver

 

[Panchdara]

Hold press... a 4mm nut driver will NOT, repeat NOT, work. The wall will be too thick. You need to get Stihl part# 5910-890-2307. Works a treat. See http://www.ebay.co.uk/itm/311006469353
But, don't tell anyone.

 

[Swamp Man]

My 4mm nut driver works but it's also a deep well

 

[Panchdara]

My 4mm nut driver works but it's also a deep well

Okay.... I got 3 deep sockets, 2 nut drivers (all 4mm) an NONE work on these carbs because the walls are too thick. I have 3 Stihl 5910-890-2307 4mm nut drivers and they all work. Zama made a narrower entrance on the newer carbs. Here are the ODs of the deep sockets:
6.64/6.75/6.54 - mm
OD of the nut drivers"
6.90/6.88 - mm

OD of the Stihl tool (5910-890-2307):
5.55 - mm

So the Stihl/Zama is 1.25mm smaller OD than the conventional drivers. (And even that is a tight fit)

Perhaps Zama changed their design?

 

[GrassGuerilla]

FWIW, I'd leave the 4-mix as is. They are somewhat known for problematic carbon build up. If I'm not mistaken they (the trimmers) were the reason Stihl developed the Ultra oil. In an effort to reduce or eliminate carbon build up on the exhaust valve. I think the problems were limited to early production units some years back. I have a couple 4-mixers that have been good performers and trouble free. Tinkering with the carb won't likely unleash much. I'd leave it to the dealer to keep em covered. They ain't simple 2-strokes.

 

[Panchdara]

Thanks GG. Question: what is an exhaust valve in a 2-stroke? Is it a reed type valve (sorta like a pair valve on 4-strokes?) I've not seen an exploded view of the Stihl engines - but from my experiences with 2-strokes I go by rule-of-thumb "if you see smoke, there's oil"

 

[AKDoug]

Don't mess with it. They don't really respond to screw tuning like a standard 2 stroke. They simply don't rev out like the older saws. A 1/2 turn on the H screw hardly makes a difference.

 

[GrassGuerilla]

Thanks GG. Question: what is an exhaust valve in a 2-stroke? Is it a reed type valve (sorta like a pair valve on 4-strokes?) I've not seen an exploded view of the Stihl engines - but from my experiences with 2-strokes I go by rule-of-thumb "if you see smoke, there's oil"

The br600 backpack, and fs130 are both 4-mix. Both are 4 strokes. Actually have valves and such. Some 37 moving parts. Only thing they have in common with 2-strokes is the fuel itself.

Edit: AKDoug is a Stihl dealer I believe. Heed his advise.

 

[Panchdara]

GG... you got me there... I have a FS130 and FC95 (both have same carbs), but seriously they both run like 2-strokes. I've not seen the parts manual (because I'm not "worthy"). Okay... I'll pop down to local dealer here in Sevenoaks, Kent, and see if they'll allow me to have a peek. Mind, having said that, I also have a BG86 and there is a definite difference in engines between that and the other 2. Thanks for the heads-up GG. Best

 

[Panchdara]

Point proven - GG... wow. I had no idea these small engines were 4-stroke (never even entered my equation). Oh well... I'll have to be cautious on the oil mixture. And, having seen the difference between the FS130 and the FS250, the guy is so right, the FS130 only knows stop and full! It's a pain to control in sensitive areas. (but the Stihl nut driver is the only tool I know that will adjust the Zama carbs) Thank you for your time in pointing me in the right direction. Best

 

[GrassGuerilla]

I've heard others say the fs130 is either "wot" or idling. Mine "feathers" pretty well. Might have the dealer look into setting the carbs low side properly so it will accelerate (educated guess). Typically the low side mix affects acceleration up to mid rev, where the H side takes over. Hope you get her running the way you like. They have great power when dialed in properly.

 

[Panchdara]

Ha!... yes, WOT or idle.... needs a governor! Mine purr like kittens, never miss a beat, but the throttle is quite jumpy (ie difficult to find that in-between) but the cable is smooth. Perhaps a stiffer spring on the throttle? Thanks again. I've learnt an awful lot from this thread.

Best