5. MAINTENANCE & INSPECTION 55
(6) Cleaning and Checking Water Passages
When it is used for a long time, cleaning of the cooling water passages is periodically necessary, because
trash, scales, rust, and so on collect in the cooling water passages and the cooling performance declines.
The following maintenances are necessary.
• Heat exchanger inspection.
• Pressure cap inspection.
This maintenance requires specialized knowledge. Consult your Yanmar dealer or distributor.
(7) Adjusting Tension of Alternator Driving Belt
Replace the alternator driving belt with new one every 1000 hours or four years, whichever comes first, even
if there is no crack on the belt surface.
Refer to 5.3.1(6) for the procedure.
(8) Adjusting Propeller Shaft Alignment
The rubber tension of the flexible engine mounts is lost after many hours' use. This leads to a drop in vibration
absorption performance, and also causes centering misalignment of the propeller shaft.
Be sure to replace the Yanmar flexible engine mounts every 1000 hours or 4 years, whichever comes first.
This maintenance requires specialized knowledge. Consult your Yanmar dealer or distributor.
5.3.6 Annually
(1) Replacing Fresh Water Coolant
Cooling performance drops when cooling water is contaminated with rust and scale.
Even if antifreeze or antirust is added, the cooling water must be replaced periodically because the properties
of the agent will degenerate.
To drain the fresh water/coolant, open the fresh water cocks (three) as shown in 3.2.4.
Refer to 3.2.4 for the procedures.
5.3.7 Every Two Years
Replace rubberized hoses for water and fuel periodically every two years or 2,000 hours of operation, which-
ever comes first. Consult your Yanmar dealer or distributor.
