Yanmar 3TNV Series Service Manual page 56

The cylinder to be adjusted first does not have to be the No.1 cylinder. Select and adjust the
cylinder where the piston is the nearest to the top dead center after turning, and make adjustment
for other cylinders in the order of ignition by turning the crankshaft 240
The adjustment method of reducing the flywheel turning numbers (for reference):
For 3 cylinder engines
Set No.1 cylinder to the compression T.D.C.and adjust the clearance of the
table. Next, turn the flywheel once (the suction / exhaust valve of No.1 cylinder is in the position
of the overlap T.D.C. at this time), and adjust the clearance of the
Ignition order of 3 cylinder engines: 1
Cylinder No.
Valve Suction Exhaust Suction Exhaust Suction Exhaust
No.1
compression
T.D.C
No.1
overlap
T.D.C
For 4 cylinder engines
Set No.1 cylinder to the compression T.D.C. and adjust the clearance of the
bottom table. Next, turn the flywheel once, and adjust the clearance of the
Ignition order of 3 cylinder engines: 1
Cylinder No.
Valve Suction Exhaust Suction Exhaust Suction Exhaust Suction Exhaust
No.1
compression
T.D.C
No.4
compression
T.D.C
(b) Valve clearance inspection and adjustment
1) Loosen adjusting bolts
In case of 2-valve cylinder head loosen the lock
nut and adjusting screw, and check the valve for
any inclination of valve cap, entrance of dirt or
wear.
In case of 4-valve cylinder head loosen the lock
nut and adjusting screw of rocker arm. Be careful
that excessive tension isn't applied to the valve
bridge, and loosen a locknut of valve bridge.
[NOTICE]
When loosening a locknut of a valve bridge, loosen
the locknut while fixing the valve bridge with a
wrench so that the valve may not lean.
3 2
1 2
3 4 2
1 2
41
2. Inspection and Adjustment
each time.
mark of the below
mark.
3
The first time
The second time
mark of the
mark.
3 4
The first
time
The
second
time