[carb...unresolveable fast-idle] Turned Idle so far out the screw fell out and chain still whips at idle :/

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arborjunky
Joined
Jun 25, 2019
Messages
142
Location
Tampa-Area
My groundsaw doesn't see a ton of use (it's a 42cc, my 355t is 36cc so I typically just grab that on-ground since I like its feel better) and it was having 'fast idle' issues when I last used it (~3wks ago) but when I went to 'tune&restore' it yesterday I found I could not resolve the fast-idle at all, even after turning out the Idle screw and having to put it back in*, with it back in (just barely) it was still fast chainspeed, I'd turn-down (CW) the Low jet until it'd choke out, I did this back&forth (was throttling / this isn't just 'fast-idle at startup')

If Idle is pulled-out (CCW) as far as the carb allows, and the L jet is choked off as much as the powerhead allows w/o dying at idle (low-enough that it will die if you touch that trigger), my chain is still whipping around.....WTF?!?


No idea what to do would appreciate any input, FWIW I do have a backup/parts saw for this unit but I cannot even fathom what it could be if not idle/L settings... Thanks in advance for any&all input :D

(saw is the venerable "Poulan Pro pp4218a", the backup/parts unit is Craftsman branding....this poulan is my 1st-ever chainsaw and it's held its own, it's still more powerful than my highly tuned 36cc echo! Have to wonder how much of that is "saws are better broken-in" and how much validity there is to that sentiment)


*is there supposed to be a spring on the Idle screw? When shaking my upside-down saw to retrieve the fallen Idle screw, I also had a lil black spring fall out, this spring's absence hasn't had noticeable effect on the saw..
 

J D

ArboristSite Guru
Joined
Apr 19, 2020
Messages
828
Location
NZ
If it truly is idling high all of a sudden look for something mechanical preventing the throttle from returning all the way to the adjustment screw (linkage catching/ bent, return spring broken or caked in crud etc)
If there is nothing holding the throttle up the saw has probably developed an air leak. Given it's lack of use I would suspect perished lines or seals
 
Bubster

Bubster

ArboristSite Member
Joined
Aug 22, 2021
Messages
73
Location
WV
A saw that sits a lot will get gunk between the clutch shoes and sprocket drum.Clean that out first.If no help,replace clutch springs.They are actually pretty easy to replace (and cheap)
 
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