dialing in my rebuilt Zenith 40s...issues

[speedo]

I was getting them adjusted on a rebuilt 2.4 after swapping the 115 mains and 47.5 idles for 120 mains and 50 idles. I also bumped the chokes to 28.5. Engine started up fine, but before I was going to go through and synchronize the barrels, thought I would check the floats. One was close and the other three were so far off they overflowed out the vents. Ok, pulled the new valves and noticed I had shimmed them when I rebuilt the carbs with a .75mm shim. As a .5mm equals 2mm of float level, I reinstalled with no shims. Now on the left bank rear I am good, left bank front no indication of fuel but when I pull the stop on the bowl it definitely has fuel...not sure why I am getting no reading. On the right bank, both are still overflowinig?? I pulled out my old valves and compared thinking the new valves might be shorter? Nope old valves are shorter. I can't remove any more shims...what do I do? The valves are obviously too high and not shutting off the flow of fuel. And the floats them selves don't have any adjustability. Ideas?


Speedo

[Heinz911]

I had a float level tool that went in a bit to deep. It blocked the movement of the float. This was only on the right carburator. If you remove the valve you can check if the float moves freely.

[Heinz911]

If this is the issue you can solve it with some shims on the float tool

[speedo]

Thanks Heinz.
I will check. Makes sense that if the tool blocks the movement of the float, the valve will not shut. Thanks for the response.

Speedo

[speedo]

Heinz,
You were dead on. I pulled the float bowl plugs and looked in with a mirror. In each of the holes a tiny portion of the float could be seen through the hole...at the top. The shaft of my float vial was twice as long as the bowl plug. And when I would screw it in, it would catch the piece of the float and hold it down so that the valve would just overfill the bowl. I compared the lip of the bowl to the lip on a set of webers and there was about a quarter inch difference...more material on webers which is why I never had this problem with webers. I put a big quarter inch rubber donut on the shaft and went around to all four floats without the "float binding" problem. I reset all the carbs and the engine sings.

Who would have thought!

Thanks

Speedo

[Heinz911]

You are welcome