0433717 EVINRUDE GEARCASE ASSY., Complete

For the control system to maintain the correct air/fuel ratio for the engine, an adequate pressure and quantity of fuel must be provided. Proper calibration of the gas pressure regulator will help to ensure that the engine is properly supplied with fuel.If calibration of the gas pressure regulator is not appropriate for the fuel and the operating conditions, a failure of the engine may occur. The service life of the turbocharger, the valves, and other components may be reduced.Gas Supply
To prevent particles from entering the engine, install appropriate fuel filtration.Also install a pressure gauge on each side of the fuel filter to monitor filter restriction. To facilitate servicing of the filter, a shutoff valve should be installed on the supply side of the filter.
Use only properly designated Caterpillar gas pressure regulators.
The regulator should be sized so that the supply pressure to the TecJet fuel valve is between 0.5 psig minimum at rated load and 5 psig maximum at idle. The regulator must be able to provide constant pressure to the TecJet from cranking speed to full load.Less gas pressure may result in reduced power. More gas pressure may result in instability.Fuel flow from the gas pressure regulator to the Gas Shutoff Valve (GSOV) is configured with a regulated pressure of 3.5 kPa to 35 kPa (.5 psi to 5 psi), that is required to ensure acceptable operation.The steady state fuel pressure stability requirement is 6.9 mbar/sec ( 1 psi/sec).The transient fuel pressure stability requirement is 48.2 mbar/sec ( 7 psi/sec).Check the Installation of the Gas Pressure Regulator
Illustration 1 g02411864
Line connections to the gas pressure regulator
(1) Balance line
(2) Compensation sensing lineCarefully inspect the condition of balance line (1) and compensating line (2) at both ends. Ensure that the line fittings are not leaking.Ensure that the lines are not kinked or damaged. Damage to one of the lines could compromise the operation of the gas pressure regulator. If the condition of either of the lines is questionable, replace the line.Adjusting the Gas Pressure Regulator
The gas pressure regulator maintains a pressure differential between the air and the fuel that is supplied to the fuel metering valve. After the initial setup, the gas pressure regulator will maintain the pressure differential. The setting will also provide for stable engine operation during no-load operation.Adjusting the Regulator
Ensure that the gas supply to the regulator is turned off.Note: A water manometer may be used instead of the 1U-5470 Engine Pressure Group.
Attach the lines for the differential pressure gauge of the 1U-5470 Engine Pressure Group.
Illustration 2 g02410997
Typical arrangement for a low-pressure gas engine
(1) Air filter service indicator
(2) Plug
(3) Cap
Perform the following procedure for low-pressure gas carburetors:Remove plug (1) from the fuel line to the fuel metering valve. Remove service indicator (2) from the air cleaner housing. Attach the lines for the differential pressure gauge of the 1U-5470 Engine Pressure Group into these ports.
Remove cap (3) from the housing of the gas pressure regulator.
Turn on the gas supply to the gas pressure regulator. Start the engine. Observe the pressure differential. This setting will generally be between 0.87 to 1.5 kPa (3.5 inches to 6 inches of H2O) for these engines.
If necessary, adjust the gas pressure regulator adjustment screw to obtain the desired pressure. Use the 8T-5160 Gas Regulator Setting Tool or use a large screwdriver to turn the adjustment screw. Turn the adjustment screw clockwise to increase the pressure, turn the screw counterclockwise to decrease the pressure.
Stop the engine. Turn off the gas supply to the gas pressure regulator.
Remove the lines for the differential pressure gauge. Restore the fittings to the original configuration.
Turn on the gas supply to the gas pressure regulator. Return the engine to service.