Marine propulsion unit with dual water inlet structure

An improved twin propeller marine propulsion unit. A vertical drive shaft is journaled in the lower gearcase and drives a pair of bevel gears. A pair of concentric propeller shafts are mounted in the lower torpedo section of the gearcase and each shaft carries a propeller. A slidable clutch is movable between a neutral, a forward, and a reverse position and serves to operably connect the outer propeller shaft with one of the bevel gears when the clutch is moved to the forward drive position. A gear is mounted for sliding movement in unison with the clutch and acts to operably engage the inner propeller shaft with the second bevel gear when the clutch is in the forward drive position so that both propellers are driven in opposite directions to provide forward motion for the watercraft. The propulsion unit also includes a dual cooling water pick-up system in which seawater is drawn to the water pump both through a series of vertical inlet ports in the gearcase and through a plurality of inlet holes that are located in the forward end of the lower torpedo section. Exhaust gas from the engine is discharged through the rear end of the lower housing section through axial passages in the hub of the forward propeller and then across the outer surface of the rear propeller.