Yanmar 4BY - Page 52

PERIODIC MAINTENANCE
BY Service Manual
4-9
Periodic Maintenance Schedule
Cooling
System -
Seawater
Circuit
Visual inspection of cooling
system
c
Before
starting
Check the seawater outlet
c
Before
starting
Check seawater pump belt for
wear

Check seawater filter (if
equipped) and inlet
c
Replace the zinc anodes* 
Check or replace the seawater
pump impeller
c
Air Intake and
Exhaust
System
Visual inspection
c
Before
starting
Replace turbocharger heat
shield

Check the exhaust pipe c
Check the air intake pipes c
Check the exhaust / water
mixing elbow
c
Clean or replace the air filter
element**
c
Electrical
System
Check the electrolyte level in the
battery (serviceable batteries
only)
c
Check the wiring connectors
c
Before
starting
Check alternator belt for wear 
c: Check : Replace
System Item
Periodic Maintenance Interval
Daily
Every 50
hours or
monthly
whichever
comes first
Every 250
hours or one
year
whichever
comes first
Every 500
hours or
2 years
whichever
comes first