300.9D Mini Hydraulic Excavator Caterpillar

The following conditions can affect the results of the cylinder compression test:

• Battery

• Condition of the starting motor

• Ambient conditions

• Quality of the compression gauge

Illustration 1	g02700437
Checking compression of engine

1. Remove the injector lines and the injection nozzles.

2. Set the fuel injection pump to zero delivery (disconnect the fuel cutoff solenoid)

3. Turn the engine.

4. Install a compression gauge on the cylinder to be measured.

5. Use the starter to turn the engine Read the pressure on the gauge.

6. If the measured value is at the limit or below the limit, overhaul the engine.
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   Table 2

   	Standard at Assembly	Repair Limit
   Compression Pressure(1)	32.4 ± 1 bar (470 ± 15 psi)	26 ± 1 bar (377 ± 15 psi)

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   (1)	The compression pressure is taken at 250 rpm.