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Walbro WG8 Metering Lever Height


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Anyone know the correct Walbro metering lever height for a PA125 engine?

I'm running lean on the top end, and the lever is flush with the surround at present.

To richen it up I need to raise the lever, or decrease the pop off pressure?

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  • 2 years later...

I know this is an old thread now, but I have just serviced my Walbro Wg8 fitted a Polini Thor 110 and the new metering lever supplied in the kit was preset to a height of 1.7 mm which is the same as that on the Walbro gauge. Running it now it is clearly too lean and momentarily stalls when going from idle to full power, so does anyone else know what height is best for this engine. There are a few figures quoted on the net but I cannot find a figure that relates to the Wg8 on a Polini 110.

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The lever height should be flush with the surrounding area (what the W tool specifies) - I tried different heights and they did not make that much difference to be honest.

I ended up getting some jewellers files and extending the size of the main jet.

I also found a whole lot of crud in the valve part of the main jet.

If you are having issues when you press the throttle from idle to full power, it means your L screw needs opening (counter-clockwise) - try 1/4 of a turn.

Don't underestimate the effect of the L screw - it makes the whole range of throttle richer or leaner - even the top end.

If you are still running lean at high throttle openings, then the most likely culprits are an air leak in the crankcase or crap in your carb.

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  • 5 years later...

This article will explain the lever height setting on the WH8 carb which is independent of which motor you use it on. 

Note that the Moster uses a different carb. 
The WG8 has no High mixture adjustment screw.
Instead, it has a High Jet. 
These are used on most small engines up to approx 130cc. 
The bigger engines typically use the WB32 or WB27 which has a High mixture adjusting screw. 

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