Zenith 40 TIN Float Gauge

[Super90]

Posting this in hopes it will help someone else.

I recently purchased the PMO float gauge which is used for Webers or Zenith carbs. I am using it currently on Zenith 40 TIN carbs.

It was discovered that the gauge fitting was too long and enters the float bowl and pins the float down, which causes that bowl to overfill and fuel to flow out of the bowl vent.

Ed Mayo figured it out within minutes of me bringing the carbs to him and explaining what I was experiencing. He pulled out an original Porsche float gauge and compared the two, and the fitting on the current tool is too long for the Zenith application.

The remedy is to add an additional o-ring or to turn the fitting down in a lathe. We did both.

Picture of the gauge entering the bowl and then a picture of the float and where it was being pinned.








Once the modification is done, the gauge works perfectly !! Be sure to use the lower set of lines on the gauge when using on the Zeniths.




Many thanks to Ed Mayo, as well as Chris Amond and Tom Petrushka at Mayo Performance. They patiently walked me through the full carb rebuild process. I also need to thank Paul Abbott, Kurt Donohoe and Tom Butler, who graciously made every effort to troubleshoot this issue remotely.