48IDA fuel level and float height.

[Eljaro]

I had an experience recently setting up 48IDA Webers on a 468 FE. I just took the setting and jets I had in my 482 FE and set the up on this engine.
All ran fine except the off idle was terrible and when cornering the engine would miss and stutter.
After trying all sorts of jet combinations I came to the conclusion the the float levels were incorrect.
Standard wisdom is that 5.5 to 6 mm for the float level above the carb deck is the correct adjustment.
Unfortunately carbs are inclined 10º and engine is not level but sits lower in the back,
Since the manual says that the fuel level inside the main well has to be less than 5-6mm below the nozzle bottom edge, in order to achieve that the float has to be set at 7.5mm above the carb deck.
So if you have the Weber setup with inward inclined carbs, 7.5mm is the correct float height.

[Dimis]

...and this is why I don't have an 8 stack.

A million Sundays of tinkering, I would never have been able to work that out.

I suspect this is why there are so many who swear by an 8 stack, and why so many others swear at them.

Thanks for sharing!

[Gaz64]

How are we verifying the "true fuel level"?

With the external tube method, the level can only be correct if the carbs are vertical.

The carb main well is on the same plane as the throttle shaft, so tilting the carb up to 10 degrees should not make any difference to the fuel level in the main well.
The main well should always be at an average fuel level, since it is in the middle of the bowl. An external measuring device will be inaccurate if the carbs are canted.

Of course, like many carbs, you can experiment with float level, some of Weber's level specs have large differences.

Gary