Factory carburetor metering lever settings

[Chainsaw Jim]

How well do you trust factory settings?
This is a Zama C3A carb with the metering lever set .5mm too low which is far enough to affect the performance.
It made is way onto an MS360 and out the door of a stihl dealership this way.
This isn't a brand specific occurrence and is a good reason to always check carbs after buying new or used.

 

[MustangMike]

They rebuilt a carb for the local tree guy at the local shop and the lever was about 1/16" too high. Saw just died in the cut. When he brought it back, they told him he needed to buy a new carb, so he brought it to me.

I spoke to the guy in the shop, he said he tried to get it adjusted correctly twice, and that was the best he could get it.

scary!

 

[Tor R]

Good thread Jim.
I've never seen a Walbro where the metering level isnt higher then what is recommended

 

[MustangMike]

You have to be careful, because some carbs are supposed to be set level with the lower base, and others with the top rim.

 

[wcorey]

You have to be careful, because some carbs are supposed to be set level with the lower base, and others with the top rim.

If you don't have the metering level tool, looking at a picture of one will give you a good idea of what level the lever should be flush with.

 

[MustangMike]

Bill, some carbs it is supposed to be level with the top surface, others with the lower surface. They are not all the same.

Usually the latter (I believe like the ones in a 660) have a small rod on the diaphragm.

You can use any straight edge, I often use a wide chisel.

 

[dall]

the right tools for setting them are cheap and they tell you where to use on what carb you are working on

 

[ANewSawyer]

On my Shindaiwa T25 weedeater with a TK carb, it is supposed to be below the edge by a certain amount that I don't remember. I made a feeler gauge out of popscicle stick by lapping it on sand paper. Checked it with calipers.

 

[wcorey]

Bill, some carbs it is supposed to be level with the top surface, others with the lower surface. They are not all the same.

That's exactly my point, zama and walbro at least are either one or the other and the tool either has a flat edge or one with a tit in the middle.
Tells you which surface to use, don't really need the tool then, any straight edge of the apropriate width will do.

 

[Tor R]

You have to be careful, because some carbs are supposed to be set level with the lower base, and others with the top rim.

I only have Huskies, and if I got it correct all those HDA carbs should have the metering level set flush with the body.
The first thing I do with those 346 saws is to toss the Zama in the bin

 

[MustangMike]

Got ZAMA on both my 044s and they run just fine. Got Walbro on the 460s and they run just fine also, so I don't care, I'll take either one.

 

[Tor R]

Got ZAMA on both my 044s and they run just fine. Got Walbro on the 460s and they run just fine also, so I don't care, I'll take either one.

I think the reason why I prefer Walbro is because they more or less has the same parts from Husky 242/254/262/346/357 etc

 

[Chainsaw Jim]

Here's a couple pics of two older versions of the carb tools to give as much info as possible.
On the left starting from the bottom I have a Walbro WJ, WT, and a Tillotson HS which all share similar settings where the lever sets flush with the edge of the cavity at the bottom of the pan. On the right bottom is an HD 199 and a Zama C3A which both have flat bottom pans and share the even with the carb body setting.


I also have an example of the one C3 oddball on the Zama tool. It has the confusing in between look and also has an in between setting. I set it with the tool at the exact level it requires in order to give everyone a measurement of .090 from the top of the lever to the very bottom next to the welch plugs.
I'm not sure if that's even the proper setting because the diaphragm shouldn't be banging off the little brass jet that sticks up. I adjusted it level with the outer carb body and it tuned and runs like normal.

 

[MustangMike]

If I could give you two likes I would! Ok, I'll go best answer! Thanks for the great info!

 

[94BULLITT]

Where do you find the info on how to set the metering lever on a Tillotson? They don't have info for all their carbs on their site.

 

[Chainsaw Jim]

Where do you find the info on how to set the metering lever on a Tillotson? They don't have info for all their carbs on their site.

I wish I could remember the exact Tillotson manual I stumbled across. All I remember is thinking that I should have known better since it's the same as the WJ carbs.
If you need to know a setting that isn't pictured then post a pic of the carb next to the metering diaphragm with the button visible and I should be able to tell you exactly where to set it.

 

[Chainsaw Jim]

Another thing that doesn't hurt to check is the hook on some of the replacement diaphragms like the one on the right.

On WJ carbs the little hook bottoms out before fully opening the metering pin like on this one:

Snip that little hook off and file the jagged edge smooth like the diaphragm up in the first pic on the left and you end up with the intended function:

I'm thinking those tabs and hooks are capable of wearing out faster when the plate wobbles around instead of sitting at a more stable position. And I don't believe all WJ kits have a button with that little hook on it.

 

[94BULLITT]

I wish I could remember the exact Tillotson manual I stumbled across. All I remember is thinking that I should have known better since it's the same as the WJ carbs.
If you need to know a setting that isn't pictured then post a pic of the carb next to the metering diaphragm with the button visible and I should be able to tell you exactly where to set it.

It was on an 034. The Stihl manual did not show a Tilotson. I set it up like a Zama C3 since that was the only way the manual showed it. The saw ran fine. I just like to know right spec. I'll remember to set it up like a WJ next time.

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[dall]

http://tillotson.ie/resources/

see if this has what you want

 

[94BULLITT]

http://tillotson.ie/resources/

see if this has what you want

I forget what model it was but at the time it was not on their site.

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