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What causes trimmer idle high?

#1

J

juntjoo

It's an echo pas 225. I've got a carb I soaked in acetone in there. I have three, two old and soaked in acetone and a new one which I'm holding onto til I absolutely need it. So I want to learn how these work and how to fix em when possible.

Mind you I adjusted the cable to give it more slack and made sure the little stop screw wasn't pushing it too far

So it it idles pretty high, enough to not need any throttle. Just did some trimming but eventually it dies, especially with throttle.

I'm about to YouTube "echo carb clean" see if I can get some tips on that.


#2

StarTech

StarTech

I have only used soap and water in USC to clean these. Never heard of using Acetone to clean these delicate carburetors. I do know using regular dip carburetor cleaner is a NO NO.

Does the throttle cable have slack in it at idle?


#3

J

juntjoo

StarTech said:
I have only used soap and water in USC to clean these. Never heard of using Acetone to clean these delicate carburetors. I do know using regular dip carburetor cleaner is a NO NO.

Does the throttle cable have slack in it at idle?
Click to expand...
The cable itself? No. So it's working apparently right. I JUST had been working fine before I decided to clean the carb as while it was working, it was slowly degrading in performance but not throttle issues. And it currently works too, but causes it to stall.

Okay I'll keep that in mind how delicate they are. If you happen to know a resource, maybe a vid that shows how these work let me know


#4

B

bertsmobile1

Funny enough,
Both Walbro & Zama, the people who make the carbs have service manuals , instruction videos , and parts break downs on their web sites


#5

J

juntjoo

bertsmobile1 said:
Funny enough,
Both Walbro & Zama, the people who make the carbs have service manuals , instruction videos , and parts break downs on their web sites
Click to expand...
Oh cool, I'll look into that...


#6

Hammermechanicman

Hammermechanicman

If you soaked the carbs in acetone you may have ruined the check valve. Never clean a cube carb in a solvent. There is a rubber check valve in them.


#7

J

juntjoo

Hammermechanicman said:
If you soaked the carbs in acetone you may have ruined the check valve. Never clean a cube carb in a solvent. There is a rubber check valve in them.
Click to expand...
Where would it be this valve? And what here can be cleaned? I probably would need compressed air I imagine right? I don't have that and have always had a use for it. Gotta get it. IMG_20220701_095809040.jpgIMG_20220701_095733777.jpg


#8

B

bertsmobile1

Ten or so years ago the check valves were a screw in item so they could be replaced
Now days they are pressed in and not replaceable or repairable
Usually they stick closed because throttle body cleaner softens the rubber
In your case I would guess that the acetone has dissolved it completely so it is always opes thus the main jet is always passing fuel int the engine .


#9

StarTech

StarTech

1656689999677.png
1656690280578.png
High pressure compressed air is a no no too.

As said these carburetors should be only cleaned with soap and water in an Ultrasonic cleaning machine (USC). And then only lightly air blow dried. no direct air blowing especially the check valves. Now Walbro does a specialize carburetor cleaner for their carbs if don't mind paying an arm and leg for it.

As said these check valves are usually rubber but can be either plastic or fiber glass. Plus rotary barrel really should be left alone; otherwords, in place.

And again does throttle cable slack in cable attached to carburetor when at idle. It is adjustable and you had to remove it to get the carb off.

Just note this is a fully adjustable carburetor when you got the right tools.


#10

J

juntjoo

StarTech said:
View attachment 61299
View attachment 61301
High pressure compressed air is a no no too.

As said these carburetors should be only cleaned with soap and water in an Ultrasonic cleaning machine (USC). And then only lightly air blow dried. no direct air blowing especially the check valves. Now Walbro does a specialize carburetor cleaner for their carbs if don't mind paying an arm and leg for it.

As said these check valves are usually rubber but can be either plastic or fiber glass. Plus rotary barrel really should be left alone; otherwords, in place.

And again does throttle cable slack in cable attached to carburetor when at idle. It is adjustable and you had to remove it to get the carb off.

Just note this is a fully adjustable carburetor when you got the right tools.
Click to expand...
Thanks so much!

So the check valve functions like a float bowl needle? This is what isn't closing causing auto throttle(above idle)?

You know where I can learn more in detail about these?


#11

B

bertsmobile1

The carb has 2 distinct fuel circuits
The idle circuit & main jet
the check valve is activated by the air rushing over the venturi pulling it off its seat and opening the main fuel line .
I am guessing that yours is open all the time
As previously mentioned, the check valves are no longer replaceable
In fact the service kits no longer have either the check valves or the welch plugs that cover them
And to remove the welch plug you need a sharp pin point chisel to puncture the plug then flip it out
And back to what was said in post # 4 Walbro & Zama have their repair manuals which do a really good job explaining how the carbs work available as a free download and Walbro actually has some videos


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