Bleeding the Fuel System—Engines With Mechanical Fuel Supply Pump

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High-Pressure Fluids

CAUTION: Escaping fluid under pressure can penetrate the skin causing serious injury. Relieve pressure before disconnecting fuel or other lines. Tighten all connections before applying pressure. Keep hands and body away from pinholes and nozzles which eject fluids under high pressure. Use a piece of cardboard or paper to search for leaks. Do not use your hand.

If ANY fluid is injected into the skin, it must be surgically removed within a few hours by a doctor familiar with this type injury or gangrene may result. Doctors unfamiliar with this type of injury may call the Deere & Company Medical Department in Moline, Illinois, or other knowledgeable medical source.

IMPORTANT: Do not operate the engine at high speeds or full loads just before bleeding the fuel system. Doing so may cause an injection pump failure.

Bleed the fuel system anytime the system has been opened. This includes:

• After fuel filter changes.
• Anytime fuel lines have been disconnected.
• After engine has run out of fuel.
• After pump or nozzle replacement.

Bleeding Fuel System At Filter

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Bleed Fuel System At Filter

A - Bleed Vent Screw

B - Primer Lever

1. Loosen the air bleed vent screw (A) two full turns by hand on fuel filter base.

2. Operate supply pump primer lever (B) until fuel flow is free from air bubbles.

3. Tighten bleed plug securely, continue operating hand primer until pumping action is not felt. Leave hand primer in the up position, away from the cylinder block.

4. Start engine and check for leaks.

If engine will not start, it may be necessary to bleed air from fuel system at fuel injection pump or injection nozzles as explained next.

Bleeding Fuel System at Fuel Injection Pump

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Bleed Fuel At Injection Pump

A - Fuel Return Line

1. Slightly loosen fuel return line (A) at fuel injection pump.

2. Operate fuel supply pump primer until fuel, without air bubbles, flows from fuel return line connection.

3. As soon as fuel flow is free from air bubbles, tighten fuel return line to specifications. Primer lever is spring-loaded and will return to normal position.

Item	Measurement	Specification
Fuel Injection Pump Return Line	Torque	27 N˙m (20 lb-ft)