MULTICYLINDER ENGINES
131
Strike
here
Remove plug
Core Plug Replacement
Check the condition of all core plugs in the block when-
ever the engine is out of the boat for service. If any signs
of leakage or corrosion are found around one core plug,
replace them all. Core plugs in the cylinder block prevent
damage to the block should the coolant freeze. The cylin-
der block of
3GM and 3HM engines is equipped
with cast iron, removable cylinder liners. See Cylinder
Liners in this chapter.
NOTE
A
machine shop can replace core plugs in-
expensively.
work on the engine
is necessary, have the core plugs replaced at
Sealing edge
before Installation
Removal and Installation
CA
UTZON
Do not drive core plugs into the engine cast-
ing.
will be impossible to retrieve them
and they can restrict coolant circulation, re-
sulting in serious engine damage.
1. Tap the bottom edge of the core plug with a hammer
and
Use several sharp blows to push the bottom of
the plug inward, tilting the top out (Figure 81).
2. Grip the top of the plug firmly with pliers. Pull the plug
from its bore (Figure 82) and discard.
NOTE
It is also possible to remove core plugs by
drilling a hole in the center of the plug and
prying it out with an appropriate size drift
or pin punch. When removing a large core
plug, the use of a universal impact slide
hammer is recommended.
3. Clean the plug bore thoroughly to remove all traces of
the old sealer. Inspect the bore for any damage that might
interfere with proper sealing of the new plug.
4. Coat the inside diameter of the plug bore and the outer
diameter of the new plug with sealer. Use
an
oil-resistant
sealer if the plug is to be installed in
an
oil gallery or a wa-
ter-resistant sealer for plugs installed in the water jacket.
5. Install the new core plug with an appropriate size core
plug installation tool (Figure
driver or socket. Posi-
tion the outside edge of the plug 2-3
(0.08-0.12 in.)
inside the block.
the same time.
6.
Repeat Steps 1-5 to replace each remaining core plug.
Summary of Contents for 1GM10
Page 1: ...YANMAR DIESEL INBOARD SHOP MANUAL ONE TWO 8 THREE CYLINDER ENGINES...
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Page 28: ...GENERAL INFORMATION 21 Bearing Blocks Press Shaft arm Bearing Spacer Press k 4 bed...
Page 36: ...30 CHAPTER TWO CHARGING SYSTEM TYPICAL Battery switch...
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Page 44: ...38 CHAPTER TWO LUBRICATION SYSTEM 2GM AND 2GM20 MODELS...
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Page 112: ...106 CHAPTER SIX...
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Page 145: ...FUEL INJECTION AND GOVERNOR SYSTEMS 139 FUEL INJECTION SYSTEM Fuel tank hose fuel pipe...
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Page 170: ...164 CHAPTER EIGHT CLOSED COOLING SYSTEM TYPICAL rnlxlng elbow Joint...
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Page 224: ...218 CHAPTER ELEVEN...
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