Usage:
The Overspeed Protection System is designed with controls built into a single unit to monitor several functions at the same time. The functions that are monitored are:
Engine Overspeed (OS)
This is an adjustable engine speed setting (normally 127% of rated speed) that prevents the engine from running at a speed that could cause damage.
An overspeed condition will cause relay SR1 to open and deenergize the shutoff solenoid. The deenergizing of the shutoff solenoid will cut the fuel to the engine causing the engine to shutdown.
Crank Termination (CT)
This is an adjustable engine speed setting that signals the starting motor that the engine is firing and cranking must be terminated. When the speed setting is reached, a switch will open to start the engine hour meter.
The Overspeed Protection System consists of:
Electronic Speed Switch (ESS)
Relay (SR1)
Terminal Block
Schematic
NOTE: For a more detailed schematic, refer to 3408/3412 High Performance Marine Engine Schematic, Form No. SENR5518.
1. Wire Electronic Speed Switch (ESS) according to the wiring schematic.
2. Disconnect the speed input harness connections to ESS terminals 3 and 4.
3. Measure voltage between terminals 5 and 6. Terminal 5 should be connected to -battery and terminal 6 should be connected to +battery. The voltage should be +22.0 to +27.0 VDC.
4. If voltage is not between +22.0 VDC and +27.0 VDC check the 3 amp relay (SR1) using the following procedure:
a. Check continuity between terminal 6 and terminal 11.
b. Check continuity between terminal 11 and terminal A on relay.
c. Check continuity between terminals A and B on relay.
d. Check continuity between terminal B and +battery.
e. Repair faulty components as requird.
5. Connect the 8T5200 Signal Generator/Counter Group to ESS terminals 3 and 4 using the 4C6534 Adapter Harness. Refer to Special Instruction SEHS8657 for connection procedure.
6. Refer to Special Instruction SEHS8579 for procedures on adjusting the signal from the 8T5200 Signal Generator/Counter Group and reading its' frequency.
7. Follow P-555 Crank Terminate Calibration and then P-554 Overspeed Calibration.