SU Carb question float level/leaner/richer

[glemon]

So as not to hijack a topic I am going to post here, on the Healey 3000 keeps stalling someone mentioned that if you set the float level lower you would enrichen the mixture, because you have the fuel level on a smaller part of the needle. Hence more fuel exposed to the air/vacuum.

I always assumed that if you lowered the float level the mixture got leaner because the gas level is farther away from the wash of air creating the vacuum that sucks it into the motor. To take the idea to the extreme I don't think the car would work very well if the float level was set so the gas is only present at the bottom of the jet an inch down or so.

Maybe the two factors tend to balance each other out within reasonable tolerances. I have never noticed much if any difference in operating characteristics when I have adjusted float levels whether adjusting to factory specs or (foolishly) messing with them in search of a cure to some operating issue.

Sort of an esoteric point as most would agree that the proper thing to do is set them at factory spec and adjust the carbs with the appropriate mixture and idle screws anyway.

 

[Randy Forbes]

Raising the float lever/fuel level will have the effect of enrichening the mixture__to a point.

Rather than concentrating on a specified height, I'm more concerned that the two (2) or three (3) float bowl fuel levels are as equal as possible.

With Webers, the fuel level in the well VERY MUCH has an effect on mixture strenth, though I presume your question (and my reply) is directed at Skinners Union (SU) carbs :wink:

 

[Keoke]

Maybe the two factors tend to balance each other out within reasonable tolerances.

I think that is the best answer to your question.---Keoke