5033347 JOHNSON CASE ASSY, CRANKSHAFT

Illustration 1 g00800829
Typical jacket water circuit for the 3034 Marine engineThe solid arrows indicate the direction of flow. The dashed arrows indicate the direction of flow in piping for the expansion of the coolant in the vent lines. (1) Bypass line (2) Cylinder head (3) Engine (4) Water cooled exhaust manifold (5) Jacket water pump (6) Water temperature regulator (7) Vent lines (8) Cooling system pressure cap (9) Heat exchangerCoolant is pulled from the heat exchanger (9) into the jacket water pump (5) by impeller action. The jacket water pump is located on the front left side of the engine. The jacket water pump is driven by a pulley. The crankshaft pulley turns a belt which drives the pulley of the water pump.The coolant is pumped through the engine (3). The coolant is distributed around each cylinder. At each cylinder, coolant enters the cylinder head (2). The coolant then enters the water outlet manifold. The coolant then enters the water cooled exhaust manifold (4). The coolant then flows to the water temperature regulator (6). With the water temperature regulator in the closed position, the coolant bypasses the heat exchanger (9) and flows back to the jacket water pump (5) for recirculation. With the water temperature regulator in the open position, the coolant is directed through the heat exchanger (9) and back to the water pump inlet.Raw Water Circuit
Two types of external cooling systems can be used on the 3034 Marine engine. The raw water circuit and a keel cooling system are two types of external cooling systems for the marine engine. Both systems are separate from the jacket water circuit. The raw water circuit is necessary in order to cool the jacket water. The raw water circuit removes the heat from the jacket water.
Illustration 2 g00800789
The solid arrows indicate the direction of flow. The dashed arrows indicate the direction of flow in piping for the expansion of the coolant in the vent lines. (1) Cylinder head (2) Engine block (3) Supply for the raw water (4) Auxiliary water pump (5) Cooling system pressure cap (6) Heat exchanger (7) Water injection elbowThe auxiliary water pump (4) pulls raw water into the raw water circuit through the supply for the raw water (3). The raw water then flows to the heat exchanger (6). The raw water is discharged through the exhaust in the water injection elbow (7). The raw water mixes with the exhaust. The mixture exits the vessel. The raw water performs several functions:
The raw water cools the jacket water.
The raw water cools the exhaust.
The raw water silences the exhaust.Keel Water Cooling System
Two types of external cooling systems can be used on the 3034 Marine engine. The sea water circuit and a keel cooling system are two types of external cooling systems for the marine engine. Both systems are separate from the jacket water circuit. The keel cooling system is necessary in order to cool the jacket water. The keel water cooling system removes the heat from the jacket water.
Illustration 3 g00800706
The solid arrows indicate the direction of flow. The dashed arrows indicate the direction of flow in piping for the expansion of the coolant in the vent lines. (1) Cylinder head (2) Bypass line (3) Engine (4) Marine transmission oil cooler (5) Return from the keel (6) Supply to the keel (7) Jacket water pump (8) Inlet and exhaust manifold (9) Water temperature regulator (10) Vent linesThe jacket water pump (7) pumps coolant through the keel cooler for the jacket water. The coolant then flows to the marine transmission oil cooler (4). The jacket water pump (7) pumps coolant through the engine (3). The coolant is distributed around each cylinder. At each cylinder, coolant enters the cylinder head (1). The coolant flows through the water outlet manifold and into the exhaust manifold (8). The coolant then flows to the water temperature regulator (9). With the water temperature regulator in the closed position, the coolant flows through the water temperature regulator. The coolant bypasses the keel cooler for the jacket water (7). The coolant then flows back to the jacket water pump for recirculation. With the water temperature regulator in the open position, the coolant is directed through the keel cooler for the jacket water. The coolant then passes through the keel cooler on the bottom of the hull. Raw water passes over the keel. The keel dissipates the heat. The coolant is again pumped through the circuit by the jacket water pump (7) .