PURPOSE: To obtain an engine having simple structure which is not subjected to the acceleration by arranging variable Venturi type carburetors horizontally while facing each other in the bank of V-shaped engine.

CONSTITUTION: Four variable Venturi type carburetors 12, 22, 32, 42 are provided in an upper bank comprised of front cylinders 11, 21 and rear cylinders 3, 41. Each carburetor is arranged such that the suction piston will be horizontal where carburetors 12, 22 for the front cylinder are faced each other to coincide the centers A, B while carburetors 32, 42 for the rear cylinder are also faced each other to coincide the centers C, D. Consequently the suction tube system is simplified while the entire carburetor is contained with reduced size and the motion of suction piston is never influenced by acceleration/deceleration of engine.