poncho9789

I was wondering if boring out carb venturi would cause the carb not to work the way they are ment to by not creating high and low preasure zones to suck fuel into the air stream. Does anyone know if this would harm the mixing ability of the carb or would it still work the same because of the throttle blades creating the high low preasure zones.

The reason I ask is I saw a video of how a carb works at work and it said that the venturi was steped or hour glass shaped to set up the high and low preasure zones to suck the fuel into the air stream. Is this true or does the throttle blades play a larger part in this situation?

I am not planing on doing this but the carb I had had the venturi bored out by a previous owner. My friend used the carb on his old engine and it worked fine but was just wondering.

RB83L69

Depends on the carb and the situation...

It will reduce the "signal" at the discharge nozzles, which will lean it out. On the other hand, if it's going on a bigger motor and no other carb is available or can be used (class rules or whatever) then maybe it could be helpful. But, in most cases it would make more sense to just buy a bigger carb.

The throttle blades don't affect mixture very much, all they do is control the amount of air that the engine has access to. So, it's not a "gas" pedal at all, it's really an "air" pedal.

poncho9789

I guess I am confused wouldn't the throttle blades make their own high and low preasure zones because of the way the air is coming through the carb.

RB83L69

When they're not wide open there's low pressure (otherwise known as vacuum) underneath them, and high pressure (atmospheric more or less) above them; but that has nothing to do with boring out the venturis, or the way the venturis work.