YANMAR Diesel Engine 1GM, 2GM, 3GMD, 3HM. Manual - part 13

2-b) Crank the engine and set the No. 1 (flywheel side) piston to top dead center (TDC) on
the compression stroke.

Note
Set the position at which the valve rocker arm shaft
does not move even when the crankshaft is turned to
the left and right, centered around the T mark. C.

Maintenance standard (for all models)

Intake/exhaust valves

0.20mm

1. Valve clearance adjusting screw
2. Thickness gauge

2-c)
Check and adjust the intake and exhaust valve head clearances of the No. 1 cylinder.
Loosen the valve clearance adjusting screw lock nut, adjust the clearance to the maintenance
standard with a thickness gauge, and retighten the lock nut. In the case of 2 cylinder model,
adjust the valve head clearance of the No. 2 cylinder in the same manner after turning the
crankshaft 180°.

Note
If you adust the valve head clearance of the No. 2 cylinder first, turn the crankshaft 540°.
Adjust the clearance of the No. 1 cylinder in the same manner.

In the case of 3 cylinder model, adjust the valve head clearance of the No. 3 cylinder in the same
manner after turn the crankshaft 240° and then adjust it of the No. 2 cylinder after turn the
crankshaft 240° more.

[9-5.] Washing the air intake silencer element

Wash the element inside the air intake silencer with a
neutral detergent every 250 hours of operation.

[9-6.] Electrical equipment

1) Checking of the warning lamps on the instrument panel. Check the "ON" and "OFF"
function of the warning lamps before every operation.

2) Checking and maintenance of the battery.
Proper battery maintenance is vital for dependable service.

2-a)
Keep battery clean by wiping it with a damp cloth.
Keep all connections clean and tight. Remove any corrosion, and wash terminals with a
solution of baking soda and water.

2-b)
Keep battery fully charged, especially during cold weather. If a battery charger is needed,
charge it after disconnecting battery cables from battery.

2-c)
Check level of electrolyte in each cell at least every 200 hours. If low, fill to bottom of filler
neck with distilled water.

2-d)
To check battery condition, use a battery hydrometer. Check specific gravity of electrolyte in
each cell. Charge battery if reading is below 1.215.

Caution
Keep all sparks and flames away from batteries, to avoid sparks, connect
earth cable last and disconnect it first.

Important
Do not add distilled water in freezing weather unless engine is run at least 30
minutes to ensure thorough mixing.

3) Checking and adjustment of the alternator (electric
generator) V-belt tension.
If the tension for the V-belt is too tight the V-belt may
be easily damaged. On the other hand, if the tension is
too loose, slippage results and makes it hard to generate
electricity.

3-a)
Checking the tension.
With the engine stopped, press belt midway between
pulleys and measure the "give".
Belt should give 10 mm with about 10 kg force.

3-b)
If the belt needs adjustment, loosen adjusting bolt.
Pry away from charging generator (alternator).
While holding alternator in position, tighten adjusting
bolt. A well worn or cracked belt should be replaced.

Important
Make sure there is no oil on the belt. If the belt is oily
it will slip. Immediately wipe off any oil that spills or
splashes on the belt.

1. Adjusting bolt
2. Hammer

[9-7.] Remote control cable adjustment

1) Speed control

1-a) Checking the control cable fitting. Check that the control cable is fixed at the clamp. Do
not loosen nor tighten cable too much.

Adjustment of idling engine speed
The idling sped is generally set at 850-900 rpm. In case the idling speed is too low, adjust the
following way;
Loosen the lock nut and turn the diling adjustor bolt clockwise, the engine speed will
increase.
On the other hand, in case the idling speed is too high,
turn the adjustor bolt counterclockwise and lower engine
speed.

After a suitable engine speed has been obtained, tighten
the idling adjustor bolt with the lock nut.
After resetting the idling engine speed, be sure to adjust
the speed control cable so that the speed control lever
touches the idling adjustor bolt, when the remote control
lever is in the neutral position.

1. Speed Control bolt
2. Speed Control lever
3. Idling Speed adjusting bolt

2) Clutch control

2-a)
Checking the operation lever stroke. Move the
operation lever up and down (Ahead and Astern) by
disconnecting the remote control cable. Check that
the strokes between Neutral to Forward (A) and
Neutral to Reverse (B) are nearly same.
If the strokes are not the same, see your nearest
Yanmer dealer.

1. Astern
2. Ahead

2-b)
Checking the spring joint condition.
With connecting the spring joint to the control cable, check the function of the spring of the
spring joint.
If the M5 thread does not move even when you shift the control handle, the cone inside of the
clutch might be damaged. See your Yanmar dealer.