YANMAR Diesel Engine 1GM, 2GM, 3GMD, 3HM. Manual - part 10

[9-1.] Fuel oil system

1) Fuel tank and fuel supply.

1-a) Fill the tank up.

1-b)
Drain the fuel tank every 250 hours of operation.
Open the fuel tank drain cock to drain out any foreign
matter which may have accumulated in the bottom of the
tank.
When you start the new engine for the first time or after
long storage drain after 50 hours of operation.

1. Precipitation tank
2. Drain cock

1-c)
If the vent in the fuel tank cap is obstructed, fuel will not flow. Clean the fuel tank cap and
blow dry periodically.

2) Air bleeding in the fuel system
If air enters any part of the system, with the exception of the fuel tank, fuel will not be
injected into the cylinders. Check the fuel injection "sound" in the following manner.

2-a)
Pull out the engine warm up knob and place the control lever in the "half speed" position.

2-b)
Open the delivery cock of the fuel tank.

2-c)
Loosen the fuel strainer air-bleed bolt.

2-d)
Move the priming lever of the fuel feed pump up and
down. All the air has been bled out of the fuel line when
only fuel flows out. After bleeding retighten the bolt.

1. Fuel Filter
2. Fuel feed pump
3. Priming lever

2-e)

Loosen the high pressure pipe from the fuel pump. Turn the engine with the
starter motor, and at the same time tighten the cap nut of the high pressure pipe
if fuel comes out. Perform the same operation for each cylinder.

2-f)
After bleeding air from all of the cylinders,
turn the engine by the starter motor and make
sure that the injection sound of the fuel is a
strong high pitched "hiss". Be sure each
cylinder emits this hissing sound.

3) Fuel injection timing and spray
condition

Caution

Diesel fuel escaping under
pressure can have
sufficient force to penetrate
the skin, causing serious
personal injury. Before
disconnecting lines, be sure
to relieve all pressure in the
system, be sure no
connections are damaged.
Fluid escaping from a very
small hole can be almost invisible. Use a piece of cardboard or wood,
rather than hands, to search for suspected leaks. If injured by escaping
fluid, see a doctor at once. There can be serious infection or injury if
proper medical treatment is not administered immediately.

Important

Modification or alteration of the injection pump, the injection pump
timing, or the fuel injection valves in ways not recommended by the
manufacturer will terminate the warranty obligation to the purchaser.