[QUOTE=Mark75H;104695]Its because carbs work by vacuum. If your carb is too big, there will be no vacuum and no fuel mixed with all that air the large hole lets in.

That is what sets the practical limit on carb size.............................................. ............
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Years ago, Lon Stevens told me his full house Mercs had the 3 side carbs (additional,)
but they were set to open only after the main carbs were 90% open.So the motor did not bog down. Funny thing is that Rich Fushlin told me that they helped accelleration,but NOT top end ( ?). that seems strange to me .