Operation and maintenance manual

QSB4.5 and QSB6.7 Troubleshooting Symptoms Charts
Section TS - Troubleshooting Symptoms Page TS-35
Engine Speed Surges Under Load or in Operating Range
Cause Correction
STEP 10
Fuel grade is not correct for the application or the
fuel quality is poor
.............
Operate the engine from a tank of high-quality fuel.
Refer to Fuel Recommendations and
Specifications in Section V.
OK
Go To Next Step
STEP 11
Contact a Cummins® Authorized Repair Facility