Series 50 – Section 24.3 Insufficient Fuel Oil Flow

Section 24.3
Insufficient Fuel Oil Flow

To determine if insufficient fuel oil flow is causing rough running or stalling, do the following:‪

1. Perform a fuel oil flow test; refer to "29.7 Fuel Oil Flow Test" .
2. Analyze the fuel oil flow test results.
   1. If the fuel oil rate is 246 L/hr (65 gal/hr), refer to "24.4 High Fuel Oil Temperature Return" .
   2. If the fuel oil rate is less than 246 L/hr (65 gal/hr), resolve the insufficient fuel oil flow; refer to "24.3.1 Insufficient Fuel Oil Flow Resolution" .

Section 24.3.1
Insufficient Fuel Oil Flow Resolution

Perform the following steps to resolve the insufficient fuel oil flow:‪

1. Replace the fuel filter(s); refer to "13.5.11 Fuel Filters" .

   Note: Always fill the filter(s) with clean fuel oil before installing. Turn the filter(s) until they contact the gasket fully. Then, turn them an additional two-thirds by hand.

2. Inspect the fuel lines for restrictions due to pinching, kinking or other damage. If damage is found, repair as necessary; refer to OEM guidelines.
3. Inspect the cylinder head for a correct restricted fitting. If an incorrect fitting is found, replace with a new fitting; refer to "1.2.2 Removal and Cleaning of Cylinder Head" .
4. Inspect the fuel return check valve for restrictive movement; refer to "2.8.2 Fuel Return System Check Valve" .
5. Inspect the fuel pump drive assembly. If damage is found, repair as necessary; refer to "2.5.2 Removal of Fuel Pump" .
6. Verify repairs done to correct insufficient fuel oil flow; refer to "24.3.1.1 Test the Engine with Resolved Fuel Oil Flow" .

Section 24.3.1.1
Test the Engine with Resolved Fuel Oil Flow

Perform the following steps to determine if the fuel oil flow resolution resolved rough running or stalling: ‪

1. Start and run the engine.
2. Run the engine at idle with a no-load for approximately 5 minutes, allowing the engine coolant to reach normal operating range, 88-96°C (190-210°F).
   1. If the engine is not running rough or stalling, no further troubleshooting is required. Shut the engine down.
   2. If the engine is running rough or stalling, shut the engine down. Check for high fuel oil temperature return; refer to "24.4 High Fuel Oil Temperature Return" .