812443 1 Mercury RETAINER

Introduction
Do not perform any procedure in the Special Instruction until you have read the information and you understand the information.This Special Instruction provides necessary information to install the four-piece electrical wire harness assembly on 3524B Engines in 797 and 797B low altitude Off-Highway Trucks. The changes to the new electrical wire harness assembly provide improved reliability and improved serviceability.To improve reliability, the 172-8660 Oil Liquid Level Switch has been replaced with the 330-9321 Liquid Level Sensor Gp . The new sensor operates by a change in capacitance and has no moving parts. The new sensor is powered, and has three wires (power, signal, and ground). The new engine harness assembly is designed to use the 330-9321 Liquid Level Sensor Gp and will not work with the 172-8660 Liquid Level Switch . Replace the 172-8660 Liquid Level Switch on the front engine oil sump, the rear engine oil sump, and the torque converter sump.The improved wiring harness is compatible with the coolant pressure sensor, which replaces the coolant flow switch. The fuel pressure sensors replace the differential pressure switch. If the coolant pressure sensor and fuel pressure sensors are installed, the engine ECM software must be updated. Refer to Special Instruction, REHS7127 for details.Obtain the suggested tools and equipment prior to installation. If the tools and equipment are not available, assembly will be more difficult and more time will be necessary to complete the assembly.Modification of the 205-4811 Plate As for the 797 Series B Truck Engine
Note: In the following steps the 205-4811 Plate Assembly will be referred to as the stiffener plate.Note: The stiffener plate between the front and the rear engine modules must be modified before the engine harness assembly can be installed.The stiffener plate for the 797 Series B Truck with (S/N: JSM) uses a one-piece plate. You will add the required holes on both sides of the one-piece plate.On the right side of both engines, the harness assemblies and the cable assembly for the right front alternator cross under the stiffener plate.Drill and tap holes into the bottom side of the plate assembly in order to install the required clamp assemblies for the harnesses. Drill and tap holes into the top side of the stiffener in order to install supports for the ECM mounting brackets.There will be eight new holes on the bottom side of the stiffener plate for the harness clamps. There will be four new holes on the top side of the stiffener plate for the bracket supports.
Illustration 1 g02344556
Top Side of 205-4811 Plate As (Z) 3/8 -16 holes
Use a suitable lifting device to position the stiffener plate with the top side up. The weight of the stiffener plate is approximately 100 kg (220 lb).
Drill and tap four 3/8 - 16 holes (Z) to a depth of 17 mm (0.67 inch) on the top side of the stiffener plate, as indicated in the above graphic. Refer to Illustration 1.
Illustration 2 g02346737
Bottom Side of 205-4811 Plate As (Z) 3/8 -16 holes
Use a suitable lifting device to turn the stiffener plate over with the bottom side up. The weight of the stiffener plate is approximately 100 kg (220 lb).
On the bottom side of the stiffener plate drill and tap eight 3/8 - 16 holes (Z) to a depth of 17 mm (0.67 inch). Refer to Illustration 3 for the hole locations.
To install the 205-4811 Plate As , refer to the Disassembly and Assembly Manual.Modification of the 195-3788 Plate As and the 195-3789 Plate As for the 797 Series A Truck Engine
The stiffener plate for the 797 Series A Truck with (S/N: 5YW) is composed of a two-piece plate assembly. You will add the required holes to both plate assemblies.On both engines, the harnesses and the cable assembly for the right front alternator cross under the two-piece plate assembly.Drill and tap holes into the bottom side of both plate assemblies in order to install the clamp assemblies for the harnesses. Drill and tap holes into the top side of both plate assemblies in order to install supports for the ECM mounting brackets.
Illustration 3 g02244835
Top side of 195-3788 Plate As (z) 3/8 -16 holes Holes
Use a suitable lifting device to position 195-3788 Plate As with the top side up. The weight of the stiffener plate is approximately 137 kg (302 lb).
Drill and tap two 3/8 - 16 holes (Z) to a depth of 17 mm (0.67 inch) on the top side of the stiffener plate. Refer to Illustration 3.