Usage:
3408 (99U),
3412 (60M) Marine Engines
In certain applications these engines may have more than an acceptable amount of black smoke during acceleration. The air/fuel ratio control setting for each engine is set at the factory to the maximum permissible amount of fuel. The engine information plate contains the performance specifications and the dynamic air/fuel ratio control setting. Due to variations in driven equipment and the inertia and torque demands to accelerate the entire system, the factory setting may not be appropriate for every application.
The air/fuel ratio control can be adjusted to a more restrictive setting that will decrease the amount of fuel and black smoke without affecting engine reliability. The procedure for adjusting the air/fuel ratio control setting is explained in the "Systems Operation Testing And Adjusting" module in the service manual. This adjustment should be made by a Caterpillar Dealer.
A more restrictive air/fuel ratio control setting will also cause the engine to be less responsive during acceleration. The air/fuel ratio control should be adjusted to achieve an acceptable balance between engine response and black smoke during acceleration.