dialing in my rebuilt Zenith 40s...issues
 

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? :confused:


Speedo

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.

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

Inteesting idea...
 

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

Heinz911
 

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. :D

Who would have thought!

Thanks

Speedo

You are welcome