Rotary Fuel System Bleeding Procedure

The following is a generic procedure for informational purposes only. Please refer to an engine manual for exact OEM procedures.
After removal and installation of a rotary injection system, the system must be primed for proper start up and operation. In order to conduct this priming procedure, you will need a clean alternate source of fuel, at least three gallons, hosing and basic hand tools.
1. Place the container of fuel as close to and below the injection pump.
2. Install a clear fuel resistant line to the fuel inlet.
3. Disconnect the return of the fuel system from the pump. Either install a temporary return line or provide a means of capturing any fuel that comes out the return.
4. Crack all injector lines but leave the line nuts finger tight.
5. Ensure that you have proper voltage if you have an electric kill switch or place the pump shut off in the run position. (please note: if you have an electric kill switch, do not provide voltage until you are ready to prime the system as many solenoids use the fuel as a cooling agent for the switch and it can be damaged by voltage being applied without the fuel)
6. Make sure you have sufficient cranking voltage. Freshly charged batteries will greatly reduce crank time during priming.
7. Crank the engine over and observe the fuel traveling up the supply line. Once it make it to the pump intake, stop the cranking and insure that the fuel remains in the line.
8. Continue to crank until you begin to get a fuel/air mixture coming out one of the injection lines. It will appear as a white, foaming froth. Once you observe that, torque that injection line. Repeat as needed with the remaining lines.
9. Once the engine cranks, give it 1-3 minutes of run time. The engine will appear to miss and white smoke at this time.
10. Install the return line and observe engine operation. If the engine dies after the return line is installed, check for a restriction in the return system.
11. Disconnect the temporary fuel source and reconnect the system to the primary fuel supply system. If the unit fails to start after this connection, check for a compromised supply system and correct as needed.
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.
Bleed the fuel system anytime the fuel system has been opened up.
This includes:
• After fuel filter changes.
• After injection pump or nozzle replacement.
• Anytime fuel lines have been disconnected.
• After engine has run out of fuel.
Fuel Injection Pump RG6264-UN-03NOV97 Stanadyne Rotary Fuel Injection Pump A - Fuel Return Line Connector On Stanadyne rotary pumps:
1. Slightly loosen fuel return line connector (A) at fuel injection pump.
2. Operate fuel supply pump primer lever until fuel, without air bubbles, flows from fuel return line connection.
3. Tighten return line connector to 27 N˙m (20 lb-ft).
4. Primer lever is spring-loaded and will return to normal position

On Lucas rotary pumps:
RG7948-UN-13NOV97 Lucas Rotary Fuel Injection Pumps B - Bleed Screw C - Screw
1. Loosen bleed screw (B) on pump cover. NOTE: On Models DP200/201/203 Injection Pumps, bleed screw is located on top of cover near the fuel return line. 2. Operate fuel supply pump primer lever or turn ignition switch to “ON”.
3. Wait until fuel flow is free of air bubbles. Tighten bleed screw.
4. Primer lever is spring loaded and will return to normal position.
CAUTION: NEVER loosen screw (C) securing pump head, otherwise pump damage may occur.
On DENSO and Motorpal in-line pumps:
1. On DENSO pump shown, unscrew hand primer on fuel supply pump until it can be pulled by hand.
2. Open fuel filter port plug.
3. Operate the hand primer until a smooth flow of fuel, free of bubbles, comes out of the filter plug hole.
4. Simultaneously stroke the hand primer down and close the filter port plug. This prevents air from entering the system. Tighten plug securely. DO NOT over tighten.
5. IMPORTANT: Be sure hand primer is all the way down in barrel before tightening to prevent internal thread damage. On DENSO pump shown, lock hand primer in position.
At Fuel Injection Nozzles RG7725-UN-08JAN97 Fuel Line Connection
1. Move the engine speed control lever to half throttle position. On engines equipped with electronic fuel shut-off solenoid, energize solenoid.
2. Using two open-end wrenches, loosen fuel line connection at injection nozzle as shown.
3. Crank engine over with starter motor, (but do not start engine), until fuel free from bubbles flows out of loosened connection.
4. Retighten connection to 27 N˙m (20 lb-ft).
5. Repeat procedure for remaining injection nozzles (if necessary) until all air has been removed from fuel system. If engine still will not start, see your authorized servicing dealer or engine distributor
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