This article mainly introduces 3JH2 Series Maring Diesel Engine Inspection of fuel injection pump
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(1) Inspection of plunger
1) Thoroughly wash the plungers, and replace plungersthat have scratches on the plunger lead or are dis.
colored.
2) The plunger is in good condition if it slides down smoothly when it is tiited about 60. Repeat this several times while turning the plunger. Repair or replace if it slides down too quickly or if it stops part way.
(2)Inspection of delivery valve
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1) Replace as a set if the delivery valve suck-back collar or seat are scratched, scored, scuffed, worn, etc.
2) The valve is in good condition if it returns when released after being pushed it down with your finger(while the holes in the bottom of the delivery guide seat are covered). Replace if necessary.
3) Likewise, the valve should completely close by its own weight when you take your finger off the holes in the bottom of the delivery guide sheet.
NOTE: When fitting new parts, wash with diesel oil and perform the above inspection.
(3) Inspection of pump
1) Inspect for extreme wear of roller guide sliding surface. Scratches on the roller pin sliding surface are not a problem.
2) Inspect the plunger barrel seat.
If there are burrs or discoloration, repair or replace as this will lead to dilution of the iubricant.
(4) Inspection of fuel camshaft and bearings
1) Fuel camshaft Inspect for scratches or wear of camshaft, deformation
of key grooves and deformation of screws on both ends, and replace if necessary.
2) Bearings Replace if the taper rollers or outer race surface is flak-
ed or worn.
NOTE: Replace fuel camshafts and bearings together.
(5) Inspection of roller guide assembly
1) Roller
NOTE: Replace fuel camshafts and bearings together.
(5) Inspection of roller guide assembly
1) Roller
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Replace if the surface is worn or flaked.
2) Rolter Guide Replace if the outer roller pin hole is extensively worn or there are many scratches.
3) Replace if the play of the roller guide assembly pin/roller is 0.2mm(0.0078in.) or more.
4) Injection timing adjustment boft Replace if the surface in contact with the plunger side is unevenly or excessively worn.
(6) Inspection of rack and pinion
1) Rack
Inspect for bending of rack and wear or deformation of fit with pinion.
2) Pinion Inspect for wear or deformation of fit with rack.
NOTE: If the tooth surface or sliding surlace is not in good working order, rack resistance increases, affecting the condition of the engine (rough rom, over running, etc.).
(7) inspection of plunger spring and delivery spring Inspect springs for scratches, cracks, breakage, uneven wear and rust.
(8) Inspection of oil seais Inspect oit seals to see if they are burred or scratched.
(9) inspection of roller guide stop Inspect the side of the tip, replace if excessively worn.
(10) Inspection of O-rings Inspect and replace if they are burred or cracked.
