5031921 EVINRUDE GASKET, Cylinder head cover

Introduction
This Special Instruction provides the procedure in order to repower a 631D/633D/637D/639D Wheel Tractor. The replacement engine will be a Tier II level 3408E engine. See table 1 for the engine arrangement numbers. The 631D/633D/637D/639D Wheel Tractor was originally equipped with a 3408B engine. The original 3408B engine is not regulated for emissions. This Special Instruction will provide the information in order to install the Tier II level replacement engine.
Table 1
Engine Arrangement    
Original Engine     Replacement Engine    
2W-0631     256-7541    
4N-6724    
8N-7812    This Special Instruction does not include procedures that can be found in your existing manuals. Refer to the original Service Manual, Parts Manual, and Operation and Maintenance Manual for more information.When you have completed this procedure, prepare the machine for service. Refer to the Operation and Maintenance Manual.Note: Do not perform any procedure in this Special Instruction until the information has been read and understood.ReferenceService Manual, Parts Manual, Operation and Maintenance Manual.Note: This instruction contains some procedures that come from dealer feedback. If errors are found please submit feedback in SIS Web or contact the Emissions Retrofit Group.Safety
Personal injury or death can result from sudden machine movement.Sudden movement of the machine can cause injury to persons on or near the machine.To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.
Do not attempt to assemble this machine until you read and you understand the assembly instructions.Improper assembly procedures could result in injury or death.
Personal injury or death can result from improper lifting or blocking.When a hoist or jack is used to lift any part or component, stand clear of the area. Be sure the hoist or jack has the correct capacity to lift a component. Install blocks or stands before performance of any work under a heavy component.Approximate weights of the components are shown. Clean all surfaces where parts are to be installed.
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.Refer to Special Publication, NENG2500, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Welding on Electronically Controlled Engines
Proper welding procedures are necessary in order to avoid damage to electronic controls. Perform welding on the engine according to the following procedure.
Set the engine control to the "STOP" mode.
Turn OFF the fuel supply to the engine.
Disconnect the negative terminal from the battery.
Disconnect the engine's electronic components from the wiring harnesses: ECM, throttle actuator, actuator for the turbocharger compressor's bypass, fuel metering valve and sensors.
Protect the wiring harnesses from welding debris and/or from welding spatter.
Do NOT use electrical components (ECM or ECM sensors) or electronic component grounding points for grounding the welder.
Connect the welder's ground cable directly to the engine component that will be welded. Place the clamp as close as possible to the weld in order to reduce the possibility of welding current damage to the engine bearings, to the electrical components, and to other engine components.
Use standard welding procedures to weld the materials together.Parts Needed
Note: The required parts are subject to some change. Refer to TMI for the most recent required parts list.
Table 2
263-5504 Conversion Kit    
Qty     Pt. No.     Description    
1     295-4651     Cooling System Conversion Gp    
1     295-4653     Electrical Conversion Gp    
1     298-5967     Enclosure Conversion Gp    
1     295-4652     Intake and Exhaust Conversion Gp    
1     256-7541     Basic Engine Ar    
1     295-4655     Engine Installation Gp    Procedure to Install the Repower Engine In the Machine
Removal of the Engine
Remove the original engine. Refer to the