Lycoming YO-233-B2A - Page 96

TEO-540-A1A Engine Maintenance Manual
12-30 © 2021 Avco Corporation. All Rights Reserved
Page 76 February 2021
YO-233-B2A Engine Maintenance Manual
Table 1 (Cont.)
Fault Isolation Guide
Problem
Cause
Corrective Action
Ref.
Rough Idle (Cont.)
Cracked engine mounts or
defective mount bushings
Replace in accordance with
airframe and part
manufacturer’s instructions.
Engine mount bushing
incorrectly installed
Install in accordance with
manufacturer’s instructions.
Engine mount bushing
incorrectly installed
Install in accordance with
manufacturer’s instructions.
Low fuel pressure
Replace fuel pump or fuel
pressure regulator.
OHM
Uneven cylinder
compression
1. Complete the cylinder
compression check.
2. Complete the borescope
inspection of low
cylinder(s) to determine if
further disassembly and
repairs are necessary.
72-30
Ignition leads
Make sure all ignition leads
are secure.
Fault in the ignition
system
1. Remove the distributor
block and examine leads
using a high-tension lead
tester.
2. Repair or replace
components as necessary.
3. Remove spark plugs,
examine, clean, gap, test,
and replace as necessary.
IOM
Engine will not idle
unless the boost pump
is on
Fuel vaporizing in lines
1. Operate with cowl flaps in
the FULL OPEN position
and keep ground operation
to a minimum.
2. Operate with boost pump
on as necessary.
3. Complete the check of the
vent return line for
blockage. Clean if
necessary.