Lycoming YO-233-B2A - General Fault Isolation; Troubleshooting Common Engine Problems

TEO-540-A1A Engine Maintenance Manual
© 2021 Avco Corporation. All Rights Reserved 12-30
February 2021 Page 73
YO-233-B2A Engine Maintenance Manual
12-30 - UNSCHEDULED SERVICING
FAULT ISOLATION
1. General
A. Fault Isolation:
(1) Refer to the section “Fault Isolation Guide” in this chapter.
(2) Review maintenance logs and use applicable indicators to eliminate simple and
inexpensive solutions. A quick visual inspection of the engine can show indications of
obvious problems, such as intake and exhaust valve leaks, physical damage to ignition
wires and wiring harness, blocked breathers, gas and oil stains, etc
(3) Discuss the problem with the pilot for more details.
2. Fault Isolation Guide
1. The Fault Isolation Guide in Table 1 shows the more common and recurring problems,
causes, and corrective actions. Continue from the simplest to the most complex possible
causes.
NOTICE: The "Ref." column includes reference to "IOM" for the YO-233-B2A Engine
Installation and Operation Manual, "OHM" refers to the Direct Drive Overhaul
Manual. A numeric entry such as "72-00" refers to a chapter in this manual.
Table 1
Fault Isolation Guide
Problem
Cause
Corrective Action
Ref.
Engine will not start or
starts with difficulty
Inactive battery
Replace with a charged battery
in accordance with airframe
manufacturer’s instructions.
Incorrect starting
procedure
Obey starting procedures or
the Airframe Flight Manual.
Insufficient prime (could
be accompanied by
backfire
Increase prime. Examine
priming system for leaks.
Flooded engine
(overpriming)
1. Turn ignition switch "on"
and put the mixture control
in IDLE CUT-OFF.
2. Fully open throttle and start
the engine.
3. When the engine starts,
decrease throttle and
advance the mixture control
slowly to FULL RICH.
Faulty starter
Replace the starter.
OHM
Low fuel level
Complete the check of the fuel
supply. Service as required.