Advice on using a Pierce Manifold IDA Float Level check tool correctly


Just not sure if I have used my Pierce Manifold IDA Float Level check tool correctly, so require some advice please.

With reference to the diagram and Photo, I assume for a 48IDA I set the needle and seat gauge A to 24mm and them make sure the float is set at 5.5mm when the spring clip is set so that the float “tab” is in contact with the needle bottom.

Can this be achieved with the carbs in situ or will they have to be removed from the manifold.


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Ian Clark

Hi Nick,

Been down that road, fortunately it's not a difficult job. Having the float gauge is a real bonus.

A) Doesn't the need carburetor removed unless you want to check the gaskets between the carb base and the manifold. However the gasket between the carb top plate and body should be removed before checking float height. Note condition of gaskets, replace if suspicious.

B) More pleasant a job if there's no fuel in the bowl, unless you're into solvent abuse:)

C) To check the current float setting: Use the float gauge first to see what the needle/seat/tab alignment looks like. If you gently lift the tab on the float to meet the needle lift the needle to a seated position, if the float is lifting the gauge off the carb body, the float is to low.

Vice versa, if the gauge doesn't touch the float, the float is set too high

D) If the needle is seated by checking in step C and the tab is horizontal - nothing needs to be done. Hooray!

E) If the float needs adjusting: set the needle height first the check float height again. Adjust float tab to a correct horizontal position to allow the float gauge to just touch the float with the tab just barely seating the needle.

It would seem be be easier to work from the float gauge backwards as it's the proper float level that's desired.

Hope this helps


Pic attached: First CAV GT into Canada, 393 Ford Motorsport engine, Italian 48IDA Carburetors, ZF 5DS25, a rocket ship with leather and A/C!CAV Gulf Spec GT40 before and after Left RHD conversion.jpg