7200 SERIES MARINE TRANSMISSIONS Caterpillar


Operation Instructions

Usage:

General


7271 MARINE TRANSMISSION
1-Breather. 2-Output Shaft Seal Lube Fittings. 3-Input Shaft Flange. 4-Output Shaft Flange. 5-Emergency Lube Oil System Connection, Suction. 6-Emergency Lube Oil System Shutoff Valve. 7-Emergency Lube Oil System Connection Pressure. 8-Strainer. 9-Drain Plug. 10-Oil Filter Housing.


7231 MARINE TRANSMISSION (7241 Marine Transmission is similar)
1- Breather. 2-Strainer. 3-Oil Filter Housing. 4-Output Shaft Seal Lube Fitting. 5-Output Shaft Flange. 6-Drain Plug. 7-Oil Cooler.


7261 MARINE TRANSMISSION
1-Breather. 2-Oil Cooler. 3-Strainer. 4-Oil Filter Housing. 5-Output Shaft Seal Lube Fitting. 6-Output Shaft Flange. 7-Drain Plug. 8-Oil Level Dipstick.


7251 MARINE TRANSMISSION
1-Breather. 2-Oil Cooler. 3-Strainer. 4-Oil Filter Housing. 5-Output Shaft Seal Lube Fitting. 6-Output Shaft Flange. 7-Drain Plug. 8-Oil Level Dipstick.

Proper Marine transmission operation and maintenance are essential for long life and maximum performance. The basic operation and periodic maintenance procedures are outlined in this OPERATION GUIDE. Before starting the engine familiarize yourself with these procedures.

Your Caterpillar dealer is available for troubleshooting, testing and servicing when required.

Safety Precautions

Safety is basically common sense. A general guide of safety precautions may be listed, but each installation has its own peculiarities which cannot always be predicted and covered by rules. Past experience and common sense are needed for the necessary safety measures. Lack of attention to safety can result in serious accidents. Be alert. Watch for hazards. Use preventive measures. Correct deficiencies promptly.

Safety is EVERYONE'S Business!!

Pre-Start Checks And Procedures

1. Make a "walk-around" check of the engine and components. Correct minor adjustments before they develop into major repair jobs.
2. Check the engine crankcase oil level. The oil level must be between the ADD and the FULL marks on the dipstick.
3. The marine transmission oil level should have been checked before stopping the engine (see OPERATING PROCEDURES, Stopping). If the transmission oil was drained since stopping, be sure the proper refill quantity of oil has been added.

4. Open the sea water valve.
5. After the engine starts, check the marine transmission oil level at low idle with the marine transmission engaged. Maintain oil level between the ADD and FULL marks on the dipstick. See the LUBRICATION AND MAINTENANCE PROCEDURES.
6. At frequent intervals the gauges should be observed. Determine the normal reading for each gauge. Investigate the cause whenever there is a significant change in the reading.

Periodic monitoring and recording of the gauge readings will provide a performance history of the engine and marine transmission. As certain conditions develop, a change in a reading will indicate a problem is developing. The necessary repairs can be scheduled before the failure and unexpected downtime occurs.

Operating Engine And Marine Transmission

Instrument Panel Gauges

Marine Transmission Oil Temperature

The marine transmission oil temperature depends upon the temperature and the quantity of sea water pumped through the marine transmission oil cooler. The normal marine transmission oil temperature range is 150°F to 175°F (66°C to 79°C).

If the oil temperature is above the normal operating range:

1. Determine if the high temperature could be caused by severe operation: long periods of trolling, or numerous changes in direction of travel.
2. Check the temperature of the sea water: Determine if the water passing through the oil cooler can effectively absorb the heat from the marine transmission oil.
3. Check the oil system: Determine if the oil cooler is plugged, if the marine transmission oil pump is defective, or if the sea water cooling system is defective.
4. Check the sea water strainer: Determine if the sea water strainer is plugged, if the sea water pump or lines are defective, or if the oil temperature regulator is defective.

Marine Transmission Oil Pressure

Normal oil pressure depends on the temperature and quantity of oil pumped through the oil system. If the marine transmission oil is hot, the pressure will be less than if the oil is cold.

If the oil strainer becomes plugged, or if a leak occurs in the system, oil pressure may decrease and cause excessive clutch wear. If a restriction occurs in the oil pump outlet, in the selector valve, or in the lines, the oil pressure reading will increase and remain above the normal pressure reading. Excessive pressure for an extended period of time may either cause oil leaks or may rupture the oil filter element.

If a high oil pressure reading occurs:

1. Check the marine transmission oil temperature reading. High oil pressure may be caused by the oil being cold. Allow the oil to warm.
2. If oil temperature is normal and oil pressure is high, either the selector valve is defective, or there is restriction in the oil line after the selector valve. Contact your Caterpillar dealer.

If a low oil pressure reading occurs:

1. Check the marine transmission oil temperature reading. If the oil temperature reading is high, correct the problem(s) as discussed above.
2. Check the marine transmission oil level. If the level is low, add oil. Check for oil leaks and make repairs as needed.
3. Determine if the marine transmission oil strainer is plugged. Remove the strainer, and clean. See the LUBRICATION AND MAINTENANCE PROCEDURES.
4. If the oil temperature is normal, the oil level is normal, the strainer is clean and oil pressure is still low, either the gauge is defective, the line is plugged before the selector valve, the selector valve is defective, or the marine transmission oil pump has failed: Contact your Caterpillar dealer.

Operating Procedures

Transmission Control Operation

The marine transmission selector valve can be manually operated at the marine transmission, but is ususally operated from the pilot house. Pilot house controls must be adjusted so as to permit full travel of the selector lever on the marine transmission, and full engagement of the clutch plates.

To get underway after the engine has started and is warm:

1. Move the marine transmission control level in the desired direction to the fully engaged position.
2. Wait one second to allow complete engagement of the clutch.
3. Gradually increase engine speed as required.

To reverse direction when docking or traveling:

1. Reduce engine speed to low idle.
2. Move the marine transmission control lever to the neutral position.
3. Wait two seconds to allow the clutch plates to completely release, and the propeller to stop turning.


NOTICE

When reversing direction of travel, stop at least 2 seconds in the NEUTRAL position to allow the propeller to stop turning. A direct through-shift will cause severe shock loads to the engine, marine transmission and hull; and may cause the engine to reverse its rotation. If the engine reverses rotation, the engine and marine transmission oil pumps will stop pumping oil to the bearings. Severe damage will result.


4. Move the marine transmission control lever to the engaged postion. Prevent the propeller from stalling or reversing the engine's rotation by gradually increasing engine speed as the clutch is engaged.
5. Allow at least one second to allow complete engagement of the clutch.
6. Gradually increase engine speed as needed.

Trolling

The trolling valve is an attachment to the marine transmission and operates only in the forward direction. With the trolling valve engaged, engine speed must not exceed 650 RPM. The marine transmission oil temperature must not exceed 180°F (82°C). It may be desirable to mark the tachometer and oil temperature gauges at these two limits as a warning reminder. Proper monitoring of these gauges is necessary to prevent heat build-up in the clutch plates.

Trolling at reduced load for several hours may cause oil consumption and carbon build-up in the combustion chambers. Every 4 hours, load the engine at full speed and burn the carbon from the combustion chambers.

Stopping

Before stopping the propulsion engine:

1. Reduce engine speed to low idle with the transmission clutch engaged.
2. Check the transmission oil level with the engine running.
3. Maintain oil level between the ADD and FULL marks on the oil dipstick.
4. Move the transmission control lever to neutral position and stop the engine as per manufacturer's instructions.

After Stopping Checks and Procedures
1. Drain the sea water system if below freezing temperatures are expected;
2. Observe the service meter reading. Perform the periodic maintenance as instructed in the LUBRICATION AND MAINTENANCE CHART.

Alarm Switches

Each alarm switch is electrically connected to an indicating light, bell or horn. The alarm will continue until the condition is corrected and then the light, bell or horn will turn off.

To silence the bell or horn while repairs are being made, a two-way switch and a red indicator light may be installed. When the alarm is turned OFF, the red indicator light will light.


MARINE TRANSMISSION OIL TEMPERATURE SWITCH

High Oil Temperature Alarm:

This alarm is installed on all Caterpillar 7200 Series Marine Transmissions. The switch is located in the oil line between the oil pump and oil strainer or oil filter. If this alarm sounds, check the following:

Operating Under Abnormal Conditions

Marine Transmission Oil Pump Failure

Marine transmissions have a lubrication system which is independent from the engine lubrication system. The Caterpillar 7200 Series Marine Transmissions may be equipped with an emergency lubricating oil system, as shown in the illustration, which can provide proper lubrication to the marine transmission should the marine transmission oil pump fail.

1. Emergency Lube Oil Valve

2. Marine Transmission Case

3. Tapped Holes in Marine Transmission Case

4. Strainer

5. Emergency Lube Oil Pump

6. Output Flange

When the marine transmission oil pump fails, engagement of the clutches will become sluggish and the clutch plates will slip or disengage. The shaft bearings will not receive pressure lubrication.

To use the emergency marine transmission oil pump:

1. Stop the engine.
2. Loosen, move and bolt the handle of the emergency valve (1) into the EMERGENCY position.


EMERGENCY LUBE OIL VALVE

3. Start the emergency lube oil pump (5).
4. Observe the reading of the marine transmission oil pressure gauge.
5. Check the marine transmission oil level with the emergency pump running.
6. Maintain the oil level at the FULL mark on the dipstick.
7. If the engine is not to be started (if the vessel is going to be towed by another vessel) the propeller can now windmill in the water without causing damage to the marine transmission shaft bearings.
8. If the vessel is to continue under its own power: start and warm the engine, engage the marine transmission, and continue traveling at normal speed.

Towing

If the vessel cannot continue under its own power, it is recommended that the vessel be towed. If pressurized oil cannot be supplied to the marine transmission shaft bearings while being towed, the propeller shaft must be secured so as to prevent the turning shaft (caused by the propeller windmilling through the water) from damaging the marine transmission shaft bearings.


NOTICE

Turning of the propeller shaft without proper lubrication will damage the marine transmission shaft bearings.


After the shaft has been secured, have the towing vessel travel at slow speed in order to minimize the windmilling force on the propeller.

There are several ways of preventing shaft rotation; the correct method depends upon the turning force of the propeller, and the construction of the propeller shaft tunnel. Use the method best suited for the type of installation:

Wrapping Propeller Shaft:

1. On small vessels, wrap a heavy rope around the propeller shaft. The number of wraps needed will depend upon the mass of the propeller and propeller shaft.
2. Secure the rope in the opposite direction of shaft rotation.

Securing Companion Flange:

1. Remove one or more bolts from the companion flange coupling.
2. Bolt a chain to the companion flange.
3. Wrap the chain several times around the propeller shaft.
4. Secure the loose end of the chain at a right angle to the shaft and in opposite direction of shaft rotation.

Applying Air Actuated Shaft Brake:

For vessels equipped with a shaft brake, the shaft brake may be applied if there is air pressure available.

Come-Home Feature (Exclude 7221 and 7211):

If the marine transmission loses oil pressure, and if there is no other means for returning to port, the rear clutch pack can be compressed (engaged) by installing bolts. The clutch closest to the engine flywheel housing cannot be engaged in this manner.


NOTICE

Use the come-home feature only in an emergency. If the marine transmission lubricating oil pressure is lost, travel with extreme care and at minimum engine speed to avoid damaging the bearings.


1. The engine must be warm. If necessary, start and idle the engine until it is warm.
2. Stop the engine.
3. Remove the access cover from the transmission housing.

4. Install the number of bolts specified in the chart, 1 1/2 inches (33 mm) in length, equally spaced in the tapped holes of the pressure plate of the rear clutch. Alternately tighten the bolts to the torque shown in the chart below. The bolts must be alternately tightened so as not to bind the clutch plates.

NOTE: On 7231 and 7241 Marine Transmissions, the internal oil line and bearing cap must first be removed. After tightening all bolts to specified torque, install the oil line and bearing cap.

5. Install the access cover.
6. Start the engine.
7. With the engine running at low idle, check the marine transmission oil level. Maintain oil at the FULL mark on the dipstick to ensure splash lubrication of the shaft bearings.


NOTICE

The starter motor will be turning the diesel engine, marine transmission, propeller shaft, and propeller while cranking. Avoid creating excessive heat in the starter by overcranking: Damage can result.


8. After starting, travel with caution; usually at minimum speed.
9. To stop the vessel, stop the engine. Remove the bolts engaging the clutch when the engine is stopped.
10. Upon reaching port, disassemble and inspect the clutch plates for warpage and cracking: Damage can occur by having been mechanically engaged. Under severe operating conditions, the marine transmission should be disassembled and all bearings inspected closely.
Back to top
The names Caterpillar, John Deere, JD, JCB, Hyundai or any other original equipment manufacturers are registered trademarks of the respective original equipment manufacturers. All names, descriptions, numbers and symbols are used for reference purposes only.
CH-Part.com is in no way associated with any of the manufacturers we have listed. All manufacturer's names and descriptions are for reference only.