Carb CFM recommendations

yellow rose said

So the upshot is just because someone has to reduce the jet area of a carb to correct the fuel curve doesn't mean the carb is too big. In fact,

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In fact reducing jet area could mean that it has a strong signal. An 'oversized' carb would have weak signal.

Since we're discussing it, its probably worth describing why.

When the velocity is higher than expected through the booster(s), the pressure drop created in the booster is larger than expect.
A larger difference in pressure between the booster and pressure in the bowl will draw more fuel.


To reduce the amount of fuel relative to the air, a more restrictive jet is used.