Valve clearance adjustment:
Valve clearance shall affect engine performance. It should be checked and adjusted according
to technical maintaining stipulation. The intake valve cooling clearance is of 0.20-0.25mm,the
exhaust valve cooling clearance is of 0.25-0.30mm. The adjusting procedure as following:
Make the first cylinder piston stop at T.D.C. position when the "0" mark on crankshaft pulley
is aligned with the arrow mark on gear case cover, then check and adjust valve clearance of the
first valve (count from the engine front end) by inserting a valve clearance gauge. Turn the
crankshaft 180° subject to the cylinder working order 1 – 3 - 2 to adjust every valve clearance.
7 . F UE L S U PP LY S Y ST EM
The fuel supply system consists of delivery pump, injection pump, speed adjustor, fuel filter,
injector, delivery pipe and injection pipe etc. Fuel is delivered to fuel filter from fuel tank by
delivery pump where the fuel is filtered and transferred to injection pump by a high pressure and
atomized, then injected into chamber through injection pipe.
1) The fuel delivery pump is of piston type and assembled on the side of injection pump.
When in normal operation it is driven by the eccentric camshaft gear of' injection pump. Air inside
the system can be discharged by manual pump when necessary after the engine stopped.
2) Fuel filter cartridge is made of paper, which should be mounted correctly to ensure
completely sealing. To keep fuel clean, replace and clean the cartridge as instruction, otherwise
some elements might be choked or worn out to cause trouble or shorten service life.
3) The injection pump is BQ pump or IW pump, and the plunger diameter of injection pump is
6 or 6.5mm for swirl type engine. Lubrication oil is filled into injection pump from right upper
side until oil drop out from side pipe for complete lubrication. Oil refilling should be carried out
periodically.
I nj ec t io n p u mp d is as s emb li ng :
Try not to turn the crankshaft after the pump is disassembled so that to ensure the fuel supplies
timing. Otherwise the marks on idle gear and pump gear should be aligned again by turning tile
crankshaft.
A dj us t f uel sup p ly t im ing :
To adjust the angle, firstly discharge air in fuel system, crank the crankshaft to let injection
pump fill fuel. Dismounting injection pipe on first cylinder. Blow off the air in the hole of delivery
valve seat connector, then crank the crankshaft slowly and inspect the fuel level in delivery valve
seat connector, stop cranking immediately when fuel level waves. Check the mark on crankshaft
belt pulley to see whether the advance angle is in comply with the above mentioned specification.
Larger or smaller advance angle can be adjusted by loosening three bolts on pump connecting
plate. If the angle is larger, turn the gear seat counter clockwise a proper angle, If tile angle is
smaller, turn it clockwise for a proper angle, then tighten three bolts and check the angle again.
Adjust injection pump:
Injection pump was already adjusted, checked and lead sealed before ex--works. If
readjustment is necessary, it should be made on special testing machine at repairing workshop.
Injection pipe: inner diameter x outside diameter x length=¶l.5׶6×283mm
Injector:
Open pressure of injector and injector nozzle of every model engine refers to operation manual
page 4 and page 2.
Higher or lower injection pressure shall affect normal injection. When the part is damaged,
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