CRANKSHAFT AS 9N6221 - Caterpillar

Engine: 3304 (S/N: 6YB1-UP; 3TC1-UP; 4PC1-UP; 83Z1-UP) 3304B (S/N: DED1-UP; 1YF1-UP; 2KK1-UP; 9HK1-UP) 3306 (S/N: 2ZC1-UP; 5JC1-UP; 7KF1-UP; 85Z1-UP) 3306B (S/N: B8D1-UP; 1DG1-UP; 3RG1-UP; 2AJ1-UP; 8JJ1-UP; 2TM1-UP; 9NR1-UP; 8NS1-UP; 9DS1-UP; LRW1-UP; 1CZ1-UP) 3406 (S/N: 75Z1-UP) 3406B (S/N: 2WB1-11475; 4JK1-98; 4PM1-UP; 4RG1-UP) 3406C (S/N: 2WB11476-UP; 4JK99-UP; 4ZR1-UP; KPS1-UP; 1LS1-UP; 8FS1-UP; 9ES1-UP; LRX1-UP; 1DZ1-UP) 3406E (S/N: 9NN1-UP; 8AZ1-UP) 3408B (S/N: 2BG1-UP) 3412 (S/N: 2WJ1-UP; 4BZ1-UP; 1EZ1-UP; 3FZ1-UP; 81Z1-UP) 3412C (S/N: BAK1-UP; PTL1-UP; 5FL1-UP; 9EP1-UP; BCW1-UP; BAX1-UP; LRY1-UP) 3456 (S/N: BGA1-UP; CCB1-UP; EPE1-UP; CAH1-UP; GHJ1-UP; CBX1-UP)Power Module: PM3412 (S/N: CAJ1-UP)Introduction
The engine control governor is failing to keep the engine RPM steady on certain 3300/3400 gensets. The following tips will help resolve engine surge problems on mechanical governed 3300/3400 gensets.Fuel System Gumming Caused by Periods of Extended Shutdown
Tip A: Proper preventive maintenance for standby generator sets will prevent gumming caused by shutdown.
Refer to Operations and Maintenance Manual, SEBU6042, "Maintenance Management Schedules For Recommended Preventive Maintenance".Tip B: Recommended procedures for resolving fuel gumming issues in the field caused by extended storage time.
Case 1: Long engine storing time (greater than six months).
Remove governor. Refer to Field Repair Manuals for additional information.Note: With governor removed, de-gum or clean the tach shaft, load stop shaft, and Servo Assembly. Settings of the governor should not change.
Remove plunger and barrel assembly (one at a time).
De-gum plunger and barrel assembly with alcohol (or suitable substitute).
Wet the plunger and barrel assembly with a small amount of light oil or fuel.
Re-install the plunger and barrel assembly.
Check the rack movement. Repeat Steps 1.b and 1.e until you have free rack movement.
Re-install the governor. The settings for the governor may have to be verified.
Case 2: Moderate engine storage time (greater than four months).
Remove the fuel gallery cover.
Wet each plunger and assembly with alcohol, high-grade fuel, or a suitable substitute. Ensure that alcohol is applied to the hollow dowels that are the fill ports for the fuel.
Rotate the engine crankshaft at least 180°. Repeat Step 2.b twice.
Re-install the gallery cover.
Prime engine with high-grade fuel. Settings of the governor should not change.
Case 3: Short engine storage time (greater than two months).
Prime the fuel system with high-grade fuel.
Start the engine. Run the engine with aggressive low to high throttle exercise.Dashpot Settings and Proper Procedural Adjustment
Tip A: Correction of 3306/3406 standby generator set engines that may go into overspeed during startup (when equipped with dashpot governor arrangements).Discussion
This is a correctable problem that is somewhat characteristic of 3306 and 3406 governors. The oil drains from the dashpot when the engine has been idle for an extended period of time. As the engine cranks, oil is drawn into the dashpot by the moving dashpot plunger. Oil pressure is not an issue because the dashpot plunger draws unpressurized oil from a cavity in the governor housing. If the dashpot does not fill before the engine reaches 1500 RPM, the engine could run-up to the control system's overspeed trip limit and shutdown.To alleviate this problem in the past, dealers have used the following methods:
Used heating blankets in order to keep the