139799-0100 ZEXEL 9 411 612 354 BOSCH O-RING 9411612354 1397990100 1157492540

Adjusting the engine speeds
To adjust engine speed, remove the cooling fan and install the safety cover over the fan to prevent getting hurt. For speed adjustment specification, see 8-05.(1) The upper limit of engine speed can be adjusted with the HIGH-SPEED stopper bolt.This stopper bolt has been set properly and sealed in the factory before shipping of the engine. Never tamper with the seal unless it is necessary.(2) The lower limit of engine speed can be adjusted with the LOW-SPEED stopper bolt.(3) Never remove the sealing cap unnecessarily to adjust the torque spring set. For the proper disassembling procedure, see 4-02. CAUTION Warm up the engine (until coolant temperature rises up to 60°C or above) before adjusting engine speeds.(4) During running of the engine for speed adjustment, check the engine for gas leak, water leak, oil leak, and fuel leak.(5) After adjustment, perform engine acceleration and deceleration test to confirm that the engine is free from hunting and smoking.
HIGH-SPEED and LOW-SPEED Set BoltsChecking and adjustment of nozzles
To check and adjust the injection nozzles, use the following procedure:1. Injection start pressure(1) Remove the nozzle assembly to be tested from the cylinder head and set the nozzle on the nozzle tester.Perform air bleeding by moving the tester handle up and down.(2) Operate the handle at a speed of 60 rpm or more and read the gauge pressure of fuel injected from the nozzle.* Injection start pressure: 140 +10-0kgf/cm2 [13.7+1.0-0 MPa(3) If reading of gauge pressure is not within the specified range, disassemble the nozzle and vary thickness of the adjusting shim.Increasing or decreasing shim thickness by 0.1 mm will cause injection pressure to vary about 10 kgf/cm2 [0.98 MPa]
Testing Injection Start Pressure(4) When installing the nozzle, use the following values of tightening torque:* Nozzle tightening (to cylinder head) torque: 5.0 - 6.0 kgf m [49 - 59 N m]* Nozzle retaining nut tightening torque: 3.5 - 4.0 kgf m [34 - 39 N m]* Nozzle union collar tightening torque: 2.5 - 3.0 kgf m [25 - 29 N m]
Installing Nozzle Assembly2. Chattering testOperate the tester handle at a speed of about 1 stroke per second.(1) Needle valve oscillationIt is considered normal if the nozzle injects fuel mist, making intermittent sounds, and oscillations of the needle valve are transmitted to the handle.(2) State of fuel mist injectionThe nozzle should inject fuel mist straight in the direction of its axis. A nozzle is defective if it does not inject steadily or it injects fuel in several separate stripes.A nozzle is defective if it spills fuel accumulated on the bottom of the nozzle after chattering test. However, a very small drop of fuel remaining on the tip of nozzle after chattering test may be regarded as normal.
Charttering Test
After-spilling3. Injection testOperate the tester handle at a speed of 4 to 6 strokes per second.* A nozzle should inject fuel mist uniformly in the shape of a cone.4. Checking the compression pressure(1) Make sure of the following:(a) All of the engine oil level, air cleaner,