BobCat 753 – ENGINE COMPONENTS AND TESTING – Compression Checking

The tools listed will be needed to do the following procedure:

MEL10630 – Engine Compression Kit
MEL1352 – Compression Adapter

The engine must be at operating temperature.

Remove the glow plugs. (See Glow Plugs Removal And Installation on Page 70-70-2.)

Install the correct compression adapter (Item 1) [Figure 70-70-1] into the cylinder head.

Connect the compression gauge to the adapter [Figure 70-70-2].

Make sure the engine speed control is set at low idle.

Disconnect the fuel stop solenoid.

Crank the engine with the starter at cranking speed.

Compression Pressure should be 412-469 PSI (2840-3233 kPa)

Allowable Limit (minimum) is 370 PSI (2255 kPa)

No more than 10% variance among cylinders.

If the measurement is below the allowable limit, check the cylinder, piston ring, top clearance, valve and cylinder head.

Push the button on the compression gauge to release pressure [Figure 70-70-3].

Connect the fuel stop solenoid.