Carb adjust

glen

TreeHouser
Joined
May 12, 2014
Messages
12
I have a stihl 066 and the carb doesn't seem to be reacting to any adjustments should I try a good cleaning and rebuild or just replace carb. Here's what I've done so far new cylinder piston and rings new coil and cleaned up flywheel and of coarse new plug any recommendations would be greatly appreciated
 
Adjusting a carb or replacing it is as far as I go.

Would seem like something must be up. I've never had a carb be unaffected by h or l adjustments?

How is the saw running? I assume it must be to know that adjusting the carb makes no difference.
 
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  • #7
It's a runner but not happy with it.. it will idle but gotta constantly throttle up to keep it running this thing has been one big pain in the arse.......
 
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  • #9
Not sure..... the thing is I was able to adjust idle when I rebuilt top end then started to break it in and somewere between break in and cutting wood with it it started to act up now I can turn screws all over the place from 1.5 to 3 turns out and nothings happening even the idle I should be able to set idle up pretty high but nada.......I was thinking fuel pump diagram not pumping enough
 
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  • #11
Yes 1 is a good base line but I was told running it a tad rich meaning 1/2 turn more would keep from getting lean condition I would rather run a hair rich because I run the hell out of it it just makes for a little insurance that the bottom end is getting the lubrication it needs and that's what I mean I can turn them out to 3 and it doesn't change
 
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  • #13
I guess
I always just make sure my plug color is good that's the true test on where your carb should be set but unfortunately I haven't been able to get to that point I
 
So you have other Stihl saws that you run in that carb adjustment range? 1 and a half to 3 turns out?

Unless someone else would like to jump in here and correct me it's not a guess. A 1/2 turn on a jet on a Stihl is a huge adjustment.

Try it at 1 and 1 and see if it'll run.
 
Definitely look at the metering and pump diaphragms first for hardening when there is carb trouble. Metering is usually the first to need replacement, but might as well do both.
 
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  • #16
That's what I was thinking because what I said before I can change my adjustments out to 3 turns and no response from carb I guess I wasn't clear on why I was turning them out that far I was just seeing if it would change the way it ran.........thanks
 
Carb adjusting is not easy.
First make sure fuel pickup/filter is good, hose as well. Air filter clean and fuel fresh and correct.

Then set the carbs needles at its starting point. Look at MFG's web page it will tell you what that is if you look up carb.
This it should start and run at. After this it is fine tuning.
Set L first so it doesn't hesitate when accelerating.
After that H to set high range. Should fourstroke a tad when it is reved in air with bar/chain mounted.
Last T to set idle. Should have a strong and steady idle and NOT go up or down in rpm if tilted to sides or with bar up or down.

Often H and L interact and H is used as main nozzle.
 
That's what I was thinking because what I said before I can change my adjustments out to 3 turns and no response from carb I guess I wasn't clear on why I was turning them out that far I was just seeing if it would change the way it ran.........thanks

It's all good brother, was just trying to help out if I could. I knew the saw pros would show up sooner or later. Espescially if there was some activity in your thread.;)
 
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  • #21
Thanks everybody...... guna try and work this out over the weekend...
 
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  • #22
Do you know the internals of carb should I get cleaner go straight trough all little ports or will there be internal check valves that won't allow cleaner straight through
 
I completely disassemble the carb, shoot cleaner through it, then fairly lightly blow through all the orifices with my compressor. I have read cautionary about using high air pressure, but I don't think i have ever damaged anything. If the diaphragms need replacement, you might not have to clean, but I guess it can't hurt. Don't tighten the adjustment needles too tightly when closing them, there is risk to damaging the ends.
 
The metering needle can be bad as well, doesn't seat properly. You might want to get the complete rebuild kit that has that and also other parts that you probably don't need. :lol:
 
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