SEAL 1M8049 - Caterpillar

Direct Injection 3406 Industrial And Marine Engines (90U, 91U)A double-wall fuel injection lines group and a fuel drain group are now available as attachments for direct injection 3406 Industrial and Marine Engines (90U, 91U) used in marine applications.
These groups can not be used on 3406 Industrial and Marine Engines which have precombustion chambers.The new groups provide steel covers for the fuel injection lines and a collection and warning system for fuel leakage.
The 5N7710 Fuel Injection Lines Group provides a steel outer wall that will contain any fuel leakage from the injection lines, and adapters that permit this leakage to be drained.
The 5N7741 Fuel Drain Group has drain lines and a vented reservoir-switch unit.
If leakage occurs, the fuel will drain from the double-wall fuel injection lines, through the drain lines and into the reservoir-switch unit. When a specific amount of fuel is in the reservoir-switch unit, the switch is activated and a signal is sent to the operations area.
The problem must then be corrected and the fuel drained from the reservoir-switch unit.
The groups, which must be used together, give protection against fires and lubricant dilution (mixed with other solution), caused by fuel leakage.
The attachment groups are not available for parts service, but the separate components, shown in the charts, can be installed on direct injection 3406 Engines currently in use.
Special Instruction, Form No. SMHS7825 has complete instructions for the installation of the 5N7710 Fuel Injection Lines Group and the 5N7741 Fuel Drain Group.