Walbro WT Metering Lever Adjust Info Please

[buddie]

Can anyone tell me the physical measurement of the metering lever (to carb body) on a Walbro WT series carb? It's on my 026 that is currently on the bench. I have searched everywhere including the Chainsaw FAQ section and all over the Walbro website and can't find the measurement, mm, inch, hairs-width or otherwise. I realize there is a tool available for this but I want to do the adjustment without having to wait for a tool in the mail and I already have several measuring devices with inch and metric increments. Is this Walbro's best kept secret? This seems to be a finicky carb to set up so a recommended measurement would help get me off of the ground. I set it up initially by aligning the lever at the same height as the small boss that surrounds the needle but I want to do it right before I call it good. I am used to adjusting automobile carbs and typically there is a measurement to go by which is usually spot-on . Any help is very much appreciated!

Cheers!

 

[SugCutter]

WT89 Metering Lever Height

Shinny workshop has 0.065" (1.65mm) listed for the metering lever height on a WT89
YMMV
Sug

 

[Roanoker494]

Two different possibilities

If the carb has welch plugs
Metering lever should be .060 to .070 below a straightedge laid across the carb body.

If the carb has a circuit plate
Place a short straightedge across circuit plate. Metering lever should just touch the straightedge, without opening the inlet needle valve.

This information was printed on the back of a oem Walbro K3-SDC carb kit I bought.

 

[buddie]

I have a welch plug type Roanoker494 so if the kit says 0.060 to 0.070 then 0.065 that SigCutter suggests is right about where I need to be. Thank you both for your help!

 

[a. palmer jr.]

I have a welch plug type Roanoker494 so if the kit says 0.060 to 0.070 then 0.065 that SigCutter suggests is right about where I need to be. Thank you both for your help!

The "W" tool works very well!

 

[buddie]

The "W" tool works very well!

Thanks, I'll get one but don't have the time to wait for delivery on this particular repair. Much obliged!

 

[Bob Hyde]

Does the W tool have a setting for Walbro WT carbs?

 

[KostasVolos]

Does the W tool have a setting for Walbro WT carbs?

Yes ,it does .
Optimal lever gap is 1.65 mm .

 

[Bob Hyde]

thank you. ill make the adjustment tonight.
I did not see WT on the walbro tool for sale> Are there more model codes on rthe back side too?

 

[HarleyT]

Yeah. Keep googling, you should be able to see both sides

 

[Bob Hyde]

ok Harley. Found it thanks.
I guess i will order one up

 

[HarleyT]

Get the zama one too.

 

[Bob Hyde]

Another question for those of you at this trade for a while, if I may?
I had been using a vacuum pump I already had to test needle valves in the cube carbs. is it better to use positive pressure instead, and if so can someone tell me why?
thanks in advance, Bob

 

[hotshot]

Never use vacuum on a carb inlet test, you’ll draw the Viton needle tip into the seat & probably ruin the needle tip by cold forming a ring into it. Walbro has an excellent service manual you can read.

https://www.miniplane-usa.com/pdf/WalbroServiceManual.pdf
Always use 8 psig pressure to see if it leaks down, and it should hold that pressure all day long.

 

[pioneerguy600]

Another question for those of you at this trade for a while, if I may?
I had been using a vacuum pump I already had to test needle valves in the cube carbs. is it better to use positive pressure instead, and if so can someone tell me why?
thanks in advance, Bob

Some like to test for pop off pressure, that is testing for spring strength, the one under the metering lever in the carb. That spring needs to resist the pressure that builds in the tank from fuel vapor expansion since the newer saws tank vents only allow air to enter the tank, pressurized fuel vapor is not supposed to escape into the atmosphere.

 

[Vintage Engine Repairs]

Never use vacuum on a carb inlet test, you’ll draw the Viton needle tip into the seat & probably ruin the needle tip by cold forming a ring into it. Walbro has an excellent service manual you can read.

https://www.miniplane-usa.com/pdf/WalbroServiceManual.pdf
Always use 8 psig pressure to see if it leaks down, and it should hold that pressure all day long.

Interesting, I have never liked the idea of pressing on the needle to adjust the lever height. They say to press down on the needle end when bending the lever and that takes more force than 8psi vacuum.

 

[Okie]

Lots of info can be found at the Walbro site.

I use pressure instead of vacuum and have seen some chainsaw carbs run good that would not hold 5 psi with even new parts and slowly leak back and hold 3 psi and run good.

I've also seen some of the Walbro carbs that would not pass the leak tests in the trouble shooting guide where opening and closing the jets indicated a failure bur would run good on a saw, so you have to even take the troublshooting steps with a grain of salt.
I have found bad check valves inside some walbro that were not intended to be serviceable but I replaced them with good results. I suspect on some of the little Walbro's that the UltraSonic may have damaged the old check valves by softening the old valve too much due to the heated water. (therefore on my own eq chainsaw carbs I try kitting them without the USonic heated use at first.
Some of them little simple looking 2 cycle carbs can really be a pain.
(and sometimes the carb is not really the main problem when working on a erratic running chainsaw)

I have both the W tool and the Zama tool in my carb tool box also.

 

[Tomos770]