5121200LP Mercruiser STERN DRIVE, (1.47:1 RATIO)

Keep all parts clean from contaminants.Contaminants may cause rapid wear and shortened component life.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Dispose of all fluids according to local regulations and mandates.
Drain the coolant from the cooling system into a suitable container for storage or for disposal. Refer to Operation and Maintenance Manual, "Cooling System Coolant - Change" for the correct draining procedure.
Illustration 1 g01340072
Typical example
Disconnect the upper radiator hose from water temperature regulator housing (1) on the cylinder head.
Illustration 2 g01340075
Typical example
Remove the air inlet hose from inlet connection (3) on inlet manifold (2).
Follow Steps 4.a and 4.b in order to disconnect harness assembly (4) from coolant temperature sensor (5).
Slide the locking tab into the unlocked position.
Disconnect harness assembly (4) from coolant temperature sensor (5).
Follow Steps 5.a and 5.b in order to disconnect harness assembly (4) from boost pressure sensor (6).
Slide the locking tab into the unlocked position.
Disconnect harness assembly (4) from boost pressure sensor (6).
Follow Steps 6.a and 6.b in order to disconnect harness assembly (4) from inlet air temperature sensor (7).
Slide the locking tab into the unlocked position.
Disconnect harness assembly (4) from inlet air temperature sensor (7).
Remove all cable straps that secure harness assembly (4) to the cylinder head or to the inlet manifold. The harness assembly should be positioned in order to avoid causing an obstruction during the removal of the cylinder head.
Illustration 3 g01340077
Typical example
Loosen the tube clips for tube assembly (8). Remove tube assembly (8) for the fuel return from the cylinder head and from the transfer pump. Plug the port in the transfer pump with a new plug. Cap the tube assembly with new caps.
If the engine has a wastegate solenoid, loosen the tube clips for tube assembly (9). Remove tube assembly (9) from the wastegate solenoid and from the cylinder head. Plug the port in the wastegate solenoid with a new plug. Cap the tube assembly with new caps.
Illustration 4 g01340080
Typical example
Remove bolts (10). Remove bypass tube (11) from the cylinder head. Remove O-ring seals (12) and (13) from bypass tube (11).
Illustration 5 g01340081
Illustration 6 g01340083
Sequence for tightening the bolts for the cylinder head
Gradually loosen bolts (14) in the reverse numerical order to the tightening sequence. Refer to the illustration 6. Note: Follow the correct sequence in order to help prevent distortion of the cylinder head.
Remove bolts (14) from cylinder head (15).
Illustration 7 g01340086
Typical example
Attach a suitable lifting device (16) to cylinder head (15). Support the weight of the cylinder head. The weight of the cylinder head is approximately 66 kg (145.5 lb). Note: A spreader bar must be used in order to distribute the weight of the cylinder head during the lifting operation.
Use suitable lifting device (16) to carefully lift cylinder head (15) off the cylinder block. Note: Do not use a lever to separate the cylinder head from the cylinder block. Take care not to damage the machined surfaces of the cylinder head during the removal procedure.
Place the cylinder head on a surface that will not scratch the face of the cylinder head.