Yanmar 1GM User Manual page 59

OPERATION, LUBRICATION, MAINTENANCE AND TUNE-UP
ANODE MOUNTINGS
1GM AND 1GM10 MODELS
~hl
..---F'....
Anode
F-tRQ
Gasket
~
Lockwasher
~Bolt
53
Mounting plug
~<
GaSket~~
Anode~
CYLINDER BLOCK
Anode
Mounting plug
Gas~~
~~GaSket
CYLINDER HEAD
2GM, 2GM20, 3GM, 3GM30, 3HM AND 3HM35 MODELS
(closed) cooling system requires additional maintenance
due to the freshwater portion of the system, which in-
cludes a freshwater pump and may include an antifreeze
mixture.
Seawater (Standard) Cooling Systems
Flushing the system
Flushing procedures may differ depending upon engine
installation and the location of the water pump. Regard-
less of pump location, cooling water must always circu-
late through the water pump whenever the engine is
running to prevent damage to the pump impeller. On mod-
els equipped with a closed cooling system, both pumps
must be supplied with cooling water.
The following procedure provides steps to flush the
cooling system of engines equipped with a seawater cool-
ing system as well as the seawater portion on engines
equipped with a closed cooling system. This procedure
may be used for most engines, but modification ofthe pro-
cedure may be necessary for some installations.
1. Detach the inlet hose from the water pump.
2. Connect a hose from a water tap to the inlet of the wa-
terpump.
3. Open the water tap.
4. With the transmission in neutral, start the engine and
run at normal idle until the engine reaches normal operat-
ing temperature.
5. Observe the water being flushed from the cooling sys-
tem. When the flow is clear, shut the engine off, then shut
off the water tap.
6. Reconnect the inlet hose to the water pump.
NOTE
Refer to Chapter Eight toflush and refill the
freshwater portion of a closed cooling sys-
tem or to service the heat exchanger.