General Description; Contruction - Yanmar YSE8 Service Manual

3. GENERAL DESCRIPTION
Each of Yanmar diesel engines, models YSE8 and YSE12, comes equipped with
clutch reduction gear, which togethei with a flywheel is totally enclosed in the flywheel
housing and the clutch housing. The propeller shaft is run from the flywheel side.
The starter for electrical starting is directly mounted to the fly\rheel housing to
drive the ring gear of the nyl,heel
For chain starting, the power take-olf shaft is
chain-connected to the starting shaft located immediately above the cjlinder.
The engine
is started b]'clockwise rotation on the stern side and by counter-clockwise rotation on the
bo'i{ side.
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Construction
{
Part
Description & Specifications
1. CrI. bodr
llonoblock casting of water jacket, crankcase and
oil pan.
2. Cyl, liner
Wet tlpe made of special cast iron and coated with
special anticorrosive paint.
3. Main bearing
4 . C y l .
Side cover side: precision kelmet metal with thin
back metal.
Fl]'wheel side: Thick meta-I.
Gasket tfpe, part of monoblock including valve guides.
5. Intake/exhaust valve Mushroom ttpe.
6. Intake pipe lntak€ enenia type mad€ of st€el.
7. Exhaust silencer
Round, expansion t!pe, or water injection type'
8. Valve drive system
Tappet & valve push rod type. Parabolic suction/
exhaust cam with approach ramp.
9. C rankshaft
Stamp forged, with induction hardened journal, pin
and oil seal portions,
10. Flywheel
Mounted to clutch, enclosed in flywheel housing-
11. Piston
Made of aluminum alloj/, oval shaped.
12. Piston rings
Three compression rings, one oil scraper ring.
13. Piston pin
Float type.
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