Yanmar 3YM20 Operation Manual

Also see for 2YM15: Operation manual Operation manual Operation manual Operation manual Service manual

Yanmar 3YM20 Operation Manual Manual pdf 41 page image

4. MAINTENANCE AND INSPECTION41EN(7) Adjusting the Tension of AlternatorDriving BeltWhen there is not enough tension inthe V-belt, it will slip and the fresh wa-ter pump will fail to supply cooling wa-ter. Engine over-heating and seizurewill result.When there is too much tension in theV-belt, the belt will become damagedmore quickly and the bearing of thefresh water pump may be damaged.1. Check the tension of the V-belt bypressing down on the middle of thebelt with your finger (approx.98N(10kgf)). With proper tension, theV-belt should deflect 8-10 mm(0.315-0.393 inches).2. 2.If the V-belt deflection is out of thelimit, adjust the V-belt tension. Loosenthe set bolt and move the alternator toadjust the V-belt tension.3. Be careful not to get any oil on the V-belt. Oil on the belt causes slippingand stretching. Replace the belt if it ismarred.4.3.2 Inspection Every 50 Hrs. (orMonthly)(1) Drain the fuel/water separator.1. Close the fuel cock of a fuel tank.2. Loosen the retaining ring and removethe filter cup. Drain off any water anddirt collected inside.3. After reassembly, be sure to vent airfrom the fuel system.If air is in the fuel system, fuel cannotreach the fuel injection pump.Vent the air in the system according tothe following procedures.Fuel system air bleeding proceduresA PushA(Fuel filter)A Air bleeding bolt D Filter elementB Bracket E Filter capC O-ring F Retaining ringABCDEF