Page 27 - REPOWER REFERENCE GUIDE (2020)
P. 27
Engine Failure Diagnosis
Engine Failure Diagnosis
Section 3A - Engine Failure Diagnosis
Table of Contents
Diagnosing Engine Failures...............................................3A-2 Wet Fouling (Oil Deposits)..........................................3A-9
Determine Cause of Failure...............................................3A-2 Wet Fouling (Rust/Water Deposits).......................... 3A-10 3
Why It Is Important......................................................3A-2 Cold Fouling..............................................................3A-10
Steps to Follow........................................................... 3A-4 Overheating.............................................................. 3A-11 A
Causes for Marine Engine Failure..................................... 3A-4 High Speed Glazing..................................................3A-11
Read Engine Internals....................................................... 3A-6 Scavenger Deposits..................................................3A-11
Cylinder Head.............................................................3A-6 Preignition Damage.................................................. 3A-12
Pistons........................................................................3A-7 Reversed Coil Polarity.............................................. 3A-12
Valves.........................................................................3A-7 Splashed Deposits....................................................3A-12
Connecting Rods........................................................ 3A-8 Mechanical Damage.................................................3A-13
Cylinders.....................................................................3A-8 Piston Failures................................................................. 3A-13
Used Spark Plug Analysis..................................................3A-8 Preignition.................................................................3A-13
Normal Condition........................................................3A-9 Detonation................................................................ 3A-14
Chipped Insulator........................................................3A-9 Bearing Failures...............................................................3A-16
90-8M0149179 eng NOVEMBER 2018 © 2019 Mercury Marine Page 3A-1
