IO-390-D Series Engine Maintenance Manual
72-20
© 2020 Avco Corporation. All Rights Reserved
Page 146
March 2020
IO-390-D Series Engine Maintenance Manual
Crankshaft Inspection Checklist for IO-390-D Series Engines (Cont.)
Item
Comments
Findings/
Corrective Action
Done
Examine the gear mounting
face of the crankshaft
counterbore.
If the mounting face of the
crankshaft counterbore is
damaged, replace the crankshaft.
If there is a hole or tang on the
crankshaft gear (instead of a
slot), examine the tang for any
nicks or dents.
If nicks or dents are found,
replace the crankshaft gear with
a new three-scallop pilot flange
gear (Figure 28).
Examine and measure the
alignment dowel per
instructions in the “Alignment
Dowel Inspection” in this
chapter.
Counterweight Inspection
Figure 30
Crankshaft Counterweight, Rollers, and Bushings
NOTICE:
A crankshaft counterweight (Figure 30) cannot be repaired. It only can be replaced.*
A counterweight roller cannot be repaired. It only can be replaced as an identical
paired set specific for each counterweight.*
*Refer to the latest revision of Service Instruction Nos. SI-1012 and SI-1535 for part numbers and
instructions to replace counterweights and rollers.
