Is a polesaw supposed to have a fundamentally-different carb setup compared to a true saw?[no H&L?!]

[Cerberus]

tl;dr--- Is there some special 'class' of carbs for 2-stroke equipment? Am finding my polesaw, an old 'for-parts' pole-weedwhip, are using carbs that're throttling off a cable and can only be adjusted via the cable (IE doing an idle-speed adjustment) but NOTHING for H&L....I wanna, *gotta* , fatten/richen my mix if I'm going to mod the muff&airbox the way I want/the way I do on all my gear but if I can't alter fuel//air ratio on this carb I can't do much can I? :/ Thanks for any input, and I know - "throw it out, go buy lithium" - will have lithium soon enough and can then have this as-backup/rainy-day polesaw ;D

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So I did a restoration project (snapped-in-half PPT-266, a $600MSRP echo polesaw...seemed a worthy challenge and certainly was!), however now that I've remedied its "real problems" and have done a few jobs with it I am just getting antsier&antsier to mod it (muffler mod for zero backpressure, airbox mod for more-than enough clean air availability) but there's no frickin' H&L screws!!!!!!!!)

Have never seen this, and have a weird "rule" that I won't get a strimmer/lawn-mower/edger/etc (afraid I'd "go that path" and only want trees / large shrub&topiary in my professional life, & lil bonsai when I get home ;D ), maybe it's a norm with shaft-driven equipment? I mean, the only possible input I can see myself having is adjustment of the throttle-cable's tautness (which can't even be 'turned-up' but just 'proper', so far as I can see)

BUT---- while I figured "must be those 'hidden carb screws' I've heard of", however since then I have seen 2 things that seriously worry me there:
1- I've studied it and cannot find anything (by-eye, or by viewing a schematic of this zama carb, an RB-K112), and WAY more-distressingly(since I've been treating the powerhead like any 'ole chainsaw-powerhead!), I just watched a video on usage(by Home Depot) and they're advocating that, on cold starts, after burping/turn-over while choked, that's fine, ***but***........They then say that, after normal turn-over/'burping' while it's choked, they say to un-choke and, before pulling that cord again, they ask you to **full-throttle** that trigger!!!!
2- I feel dumb saying it but I've just realized this engine does *not* have a fast-idle, which so far as I've seen is a universal/ubiquitous feature, kinda figured it was a requisite part of the start process, but this polesaw you simply pull it once to burp it, un-choke and pull a 2nd time and it begins purring, whether it was cold or just-used, it is the smoothest engine I've ever worked with (by a major margin and I have a new 355t..) but this no-fast-idle, and hearing a reco to start a cold-unit at full throttle (this is by Home Depot, in-context of using their rental polesaws, am gonna guess they proofed/edited that properly to prevent massive damages to all their polesaws lol!!)


Thanks a TON for any help here (is it possible/advisable to change carburetors here?? Would love a larger-jet carb in this thing), it runs a bit hot and while I removed the muffler's restricter-plate to try and help(and because I do a muff&air mod to every 2-stroke in my arsenal!) but both to increase efficiency/reduce heat *and* to increase total-power I really wanna be able to do my mods but if I can't richen my carb-settings then I'll run VERY lean and be playing roulette....ugh again thanks for any help, this thing has been one heck of a project and am so stoked that it's held its own through some jobs but not being able to adjust it is driving me nuts!!!

 

[Cerberus]

FWIW, here is the vid I meant, it's my exact unit(well, 99.9%), vid's url is set to the moment she explains this "start @ full-throttle" approach...

 

[backhoelover]

Send info

 

[backhoelover]

here is this service data

 

[Cerberus]

WOW man thank you a million times over, I've got another one of these 25cc zama echo carbs (from a same-gen string trimmer of theirs, a trash/curbside pickup which yes I do if I think I can either salvage the unit or worthwhile parts, in this case it was simply 'tearing-down an Echo' like a year ago and am so glad I saved some of it as I have a carb I can fully dissemble before even touching the 266's)

Have been told there's another way (seems to be a physical opening, a widening from 2.5mm to 3mm of some jet or passage maybe the venturi itself) and that that was the only way, cannot explain how indebted I feel to you for this, not a single powerhead I own is stock there's usually a good ~10-20%+ in a powerhead if "done right" so it's been driving me nuts that my highest-quality engine (the ppt266, thing starts & purrs like nothing I've ever used) was also the only one I couldn't touch, I mean I did mod the airbox already but left the muff un-modded so the air-mod wouldn't really lean things out much as the exhaust would still be restricted, now that I can open-up H&L a lil I can slot that muffler and really let this thing rip I owe you so much dude

 

[Cerberus]

Aha ok I see what the other post I referred to meant, it's the limiter-caps' removal themselves that is the difficult/dangerous part, damn I only know the "super-heated metal pin, insert/melt-into plastic limiters, let cool, pull-out" method, gotta say that w/ my 355t it took me like half an hour and those caps were huge/easy to see, removal of these lil 2mm caps is gonna be interesting!!!!

(will say I was relieved to see that, below the caps, it's just a flathead...because my other initial thought was "none of my H&L drivers are gonna fit into this lil slot, once I get past those caps"!)

Is it dumb to think "I don't need to replace the caps"? I could always put some red permatex plugs in if it's a wise thing to do, I just can't imagine removal w/o destruction in this case (am not going to order the tool, paying & waiting, if I can simply McGuyver it out myself right now, of course!)

 

[Cerberus]

As far as the H and L adjustment screws go, the Stihl and Husqvarna pole saws both have them. The Echos use carbs with tiny little adjustment screws

heh funny you mention that as I just posted in another thread Re the removal of these, someone was kind enough to provide the manual so I know what to do, just don't have the special limiter-removal tool and am being told it's an especially difficult removal for some reason (am still not understanding why I can't simply pull/pry out the lil plugs, if anything they look easier than 'traditional' limiters like my 355t had)

 

[kneedeepinsaws]

As far as the H and L adjustment screws go, the Stihl and Husqvarna pole saws both have them. The Echos use carbs with tiny little adjustment screws

They are micro D as far as i know..
The chinese screw drivers you get from amazon do not fit very good at all...
My H het on my 3020t was filled with some kind of poxy. It would be nice to get an aftermarket carb with good ol slotted screws