Yanmar 4LHA-HTP User Manual

(3) Inspecting Inner Parts of the Seawater Pump
The discharge performance of the seawater
pump falls depending on the use.
The seawater pump must be inspected periodi-
cally. If the discharge volume of cooling
seawater has decreased: (When disassembly
servicing of the seawater pump is necessary,
consult Yanmar dealer or distributor.)
©Loosen the side cover set bolts and remove
the side cover. (4 mounting bolts)
©lluminate the inside of the the seawater
pump with a flashlight and inspect.
©When the following damage is found,
disasassembly and maintenance are necessary:
1) Cracks and loss of impeller; flaws or excessive wear of impeller tips and side faces.
If any, replace the damaged part (consult Yanmar dealer or distributor)
(Note) The impeller must be replaced periodically (every 2000 hours).
2) Damage to the wear plate
©If there is no problem with the inner parts, fit the O-ring to the groove of the joint face and
re-install the side cover.
If water leaks continuously from the water drain pipe beneath the seawater pump during
operation, disassembly and maintenance (replacement of the oil seal) is necessary.
(--[NOTICE]
The seawater pump revolves clockwise, but the impeller
blades must be installed in the counterclockwise direction.
During reassembly, be sure to install the impeller blades
correctly shown in the illustration right. When turning the
engine manually, never turn it in the reverse direction.
The impeller will be twisted and damaged.
Direction of rotation
Impeller
5.2.6 Inspection Every 2000 Hrs.
(1) Cleaning the Cooling Water System and Inspecting & Adjusting Parts
Rust and scale are deposited inside the seawater and fresh water cooling systems during long use.
This drops cooling performance, so it is necessary to clean and maintain the following parts in
addition to replacing the cooling water.
The internal contamination of the engine lube oil cooler reduces cooling efficiency and acceler-
ates lube oil cooler degeneration.
Servicing jobs above require specialized knowledge.
Consult your Yanmar dealer or distributor.
Relevant Cooling Water System Parts:
Seawater pump, engine lube oil cooler,
intercooler, fresh water pump, fresh water cooler, thermostat, etc.
-53-

Yanmar 4LHA-HTP Specifications

General

Brand	Yanmar
Model	4LHA-HTP
Category	Engine
Language	English