0391728 EVINRUDE CARB ASSY., Middle 235 only

Operation of the Caterpillar Compression Brake
Before descending a long grade or a steep grade, test the compression brake in order to ensure proper operation.
Never exceed a safe control speed.
Do not use the compression brake when the vehicle is attached to two trailers.
Do not use the compression brake when an empty trailer is pulled on wet pavement or slippery pavement. This is particularly important if the vehicle has a single drive axle.
Do not shift gears without using the clutch when the compression brake is turned on. Do not make a double clutch when the compression brake is activated. Power train damage may occur.The compression brake will not operate during the following conditions. The following conditions will temporarily interrupt the operation of the compression brake.
The temperature of the engine coolant is below 70 degrees Celcius.
The engine speed is below 1400 rpm and the vehicle speed is below 15 mph. If low braking speed is desired, choose a transmission gear that will maintain the engine rpm above 1400 rpm.Downhill Operation
On downgrades, do not coast while the clutch pedal is depressed.
Do not coast with the transmission in NEUTRAL.
If no engine power is needed, disengage the cruise control.
Select the correct gear that does not allow the engine speed (rpm) to exceed 2600 RPM.
Use the compression brake in order to control the speed of the vehicle.
Occasionally, when heavy loads or steep grades are encountered, it may be necessary to descend using a gear that is lower than the gear that is used to ascend. Maximum braking power occurs over 2200 rpm. Care should be taken at the top of a hill in order to ensure that the vehicle is in the proper gear for optimum braking.Controls for the Caterpillar Compression Brake
Standard Operator Controls
ON/OFF Switch - This switch activates the system for the compression brake.Progressive Braking Switch - This switch allows various settings for different conditions.LOW Setting - This setting will provide approximately one-third of the total available braking horsepower. This setting is typically used on flat roads when light loads are hauled.MED Setting - This setting will provide approximately two-thirds of the total available braking horsepower. This setting is typically used when the LOW setting is not adequate in order to provide the desired braking horsepower.HIGH Setting - This setting will provide full braking horsepower. This setting is typically used on downhill grades or the setting is used when heavy loads are involved. Use this setting only when there is good traction.In addition to the switch controls that were previously discussed, other switches are available. A control switch exists for the compression brake that is activated by the position of the clutch pedal. There is also a switch that is activated by the position of the accelerator pedal.The function of the compression brake operates in much the same manner regardless of a manual transmission or an automatic transmission. However, some vehicles are equipped with autoshift transmissions. In this situation, the compression brake may actuate in order to help the transmission make an upshift. This feature is controlled automatically through the transmission control module. This automatic control can happen even if the compression brake switch is in the OFF position.Maintenance for the Caterpillar Compression Brake
The maintenance of the Caterpillar compression brake should be performed in conjunction with scheduled maintenance of the valve lash. Caterpillar recommends performing maintenance of the Caterpillar compression brake at the following intervals. Use fuel consumption, mileage, service hours, or calendar time, which ever occurs first, in order to determine the maintenance intervals.
Initial 2400 km (1500 miles) or 7500 L (2000 US gal) of fuel or 400 service hours or 6 months.
Every 161000 km (100000 miles) or 56850 L (15000 US gal) of fuel or 2000 service hours or 2 years.Note: The adjustment of the actuator piston lash must be performed after the engine valve lash adjustment is performed. Make the adjustment of the actuator piston lash while the engine is stopped.
Table 1
Component     Required Maintenance    
Wiring and Terminal Connections     Inspect    
Clutch/Throttle/Buffer Screw     Inspect/Adjust    
Actuator Piston Lash Adjusting Screws     Inspect/Adjust    
Crosshead Bridges/Valve Stem Caps     Inspect    
Housing     Inspect    
Hold Down Bolts     Inspect    
Control Valve     Inspect    
Oil Seal Ring (1)     Inspect/Replace    
( 1 ) Inspect the oil seal rings for signs of wear and for signs of damage. If necessary, replace the oil seal rings. Refer to the Parts Manual for further information.