G343 INDUSTRIAL ENGINE Starting Caterpillar

1.1. Pre-Start Checks
2.1. Starting Procedure
3.2. Electric Start
4.2. Air Start
5.2. Hydraulic Start
6.2. Starting - G399 And G349 Only

Perform required periodic maintenance before starting the engine. Make a "walk-around" check of the installation. It only takes a few minutes to correct minor discrepancies. This can prevent major repairs at a later date.

Pre-Start Checks

1. Check the air cleaner service indicator. If the red piston is locked in the raised position, service the air cleaner.
2. Correct any leaks, loose bolts or covers. The fan and radiator must be clear of restrictions.


3. Check the coolant level. The radiator must be full to the bottom of the filler neck.


4. The crankcase oil level must be above the ADD mark.
5. Disconnect any battery chargers that are not protected against the starter current drain.
6. All guards must be in place. If guards are inadequate or in need of repair, notify your supervisor.

Starting Procedure

Electric Start

1. Open the raw water valve-if so equipped.
2. Open the gas valve.
3. Disengage the clutch or open the circuit breaker. Do not start an engine under load.
4. Move the controls to half engine speed position.
5. Reset any safety devices.

Safety Gauges-Push reset button on the magnetic switch and hold the oil pressure reset button in.

Electrical-turn oil pressure switch OFF.



6. Start the engine.
7. If the engine fails to start after 30 seconds of cranking, stop. Allow the starter to cool for two minutes. Turn the gas valve OFF and crank the engine for 10 to 15 seconds to purge unburned gas from the exhaust system.
8. Turn the gas valve ON and repeat cranking procedure.


Do not engage the starter when the flywheel is moving.

Clearances and tolerances are designed for operating conditions-including operating temperature. When the engine is started it takes several minutes to establish the lubricating oil film and allow the moving parts to heat up and expand. Loading a cold engine will cause shortened service life, i.e., broken rings, seized pistons, etc. This warm up period allows time for another "walk-around" check for leaks, etc.

If oil pressure fails to register, stop the engine and determine the cause. On the units with an oil pressure switch, the reset knob will move from ON to RUN automatically when oil pressure builds up. If the knob fails to move, stop the engine and determine the cause.

Air Start

Perform all electric starting preliminary checks.

Check the air supply. The air starter must have 100 PSI air pressure available. The standard receiver stores 10.5 cubic ft. (,3 cubic m) of air at 250 PSI. Pressure is reduced at the air starter motor.

Open bleed valve (on the bottom of the receiver) weekly, to drain any condensation and oil carryover.

The lubricator must be filled with oil. See the Lubrication and Maintenance Procedures.

Hydraulic Start

Perform all electric starting preliminary checks.

Check the hydraulic accumulator pressure-it must be 3000 PSI.

Starting - G399 And G349 Only

A prelube pump is used to lubricate all moving engine control parts prior to starting. When the starter control is moved to the START position, the prelube pump motor starts running and pumps oil throughout all oil passages. As oil pressure is attained in the pressure control line, the pressure control closes the circuit to the starting motors and the engine then begins to crank. When the engine starts and the starter control is released to the OFF position, the prelube pump stops and the engine oil pump provides the lubricant. Prelube times varies with oil temperature. More time is required to attain oil pressure with hot oil than with cold oil.