M11 Series – Service Manual – 007-029   Lubricating Oil Pressure Regulator (Main Rifle)

Drain the lubricating oil.

Refer to Procedure 007-025.

Remove the oil pan.

Refer to Procedure 007-025.

WARNING  Carefully remove the retainer plug. The pressure regulator spring is under compression. Personal injury can result. Wear face and eye protection.

Remove the retainer plug (1), regulator spring (2), and regulator plunger
(3).

Remove the orifice from the plunger.

Inspect the regulator plunger for scratches or scoring. If scratches are deep enough to be felt with a fingernail, the plunger

must
be replaced.

Check the orifice in the plunger to make sure it is

not
plugged. If the orifice is plugged, clean it before replacing.

NOTE: The orifice is threaded into the plunger.

Measure the free length of the regulator spring.

Use a spring compression tester to determine if the spring is defective.

Replace the spring with a new spring if it is defective.

Measure the retainer plug to determine if it is defective. If it does

not meet the specification, replace it with a new one.

WARNING  The regulator spring must be compressed to install the retainer plug. Personal injury can result. Wear face and eye protection.

NOTE: A counterbore plunger and orifice is unique to engines with a viscosity sensor. Low oil pressure will result if a solid plunger is used with a viscosity sensor.

Install the regulator plunger (3) and regulator spring (2).

Install and tighten the retainer plug (1).

Install the oil pan.

Refer to Procedure 007-025.

Fill the engine with clean 15W-40 oil.

Refer to Procedure 007-025.

NOTE: Engine oil pressure

must be indicated on the gauge within 15 seconds after starting. If oil pressure is

not registered within 15 seconds, shut off the engine immediately to avoid engine damage. Confirm the correct oil level in the oil pan.

Operate the engine at idle speed for 3 minutes to inspect for leaks.