First, see if the logo is complete. Authentic product packaging quality, the box on the writing is clear, overprint colorful. Packaging boxes, bags, should be marked with the product name, specifications, quantity, registered trademarks, factory name and telephone number and so on, and some manufacturers are still playing their own accessories marked. Some important components such as generators, distributor, fuel injection pump, etc., but also with instructions, certificates and inspector chapter, to guide the user the proper use of maintenance. Should be carefully identified when buying, to prevent buying fake and shoddy products.

Second, see the geometric dimensions with or without deformation. Some parts due to manufacturing, transportation, improper storage, easy to produce deformation. Inspection, the shaft parts can be rolled along the glass plate a circle to see if there is leakage of glass and parts with the light leakage to determine whether the bending; optional clutch disc or friction plate, you can steel, friction Film in the immediate observation of whether its warp; in the purchase of oil seal, oil seal with the skeleton should be a positive round end, with flat glass fit without deflection; no skeleton oil seal outer edge should be corrected, with hand to make it deformed , After letting go should be able to restore the status quo. In the purchase of various types of pads, should also pay attention to check the geometry and shape.

Third, see the combination of parts is flat. Parts handling, storage process, due to vibration, bump, often in conjunction with the site burr, indentation, damage or cracks, affecting the use of parts. Should pay attention to check purchase.

Fourth, look at the surface of the parts without rust. Qualified spare parts surface, both a certain degree of precision and bright finish, the more important parts, the higher the accuracy, the more stringent packaging rust and corrosion. Should pay attention to check the purchase, if found parts rust spots, moldy spots or rubber pieces cracked, loss of elasticity, or journal surface obvious turning lines, should be replaced.

Fifth, look at the surface protection is intact. Most parts are factory-coated with a protective coating. Such as the piston pin, bearing pads with paraffin protection; piston ring, cylinder liner coated with anti-rust oil and wrapping paper; valve, piston and other anti-rust oil immersed in plastic bags. If you buy the seal is found damaged, lost wrapping paper, anti-rust oil or paraffin loss, should be returned.

Sixth, see whether the loose plastic parts. Parts made up of two or more parts are pressed, glued or welded with no looseness between them. For example, the pump plunger and the adjusting arm are assembled by press fitting. Clutch driven wheel and the steel is riveted combination, the friction plate and the steel is riveted or glued; paper filter cartridges and filter paper is glued together; electrical equipment, the first is made of welded. If found to be loose when purchased, should be replaced.

Seven, to see if the rotating parts are flexible. When purchasing a rotating part assembly such as an oil pump, turn the pump shaft by hand and feel flexible without jamming. When purchasing a rolling bearing, support the inner ring of the bearing with one hand and the outer ring with the other hand. The outer ring should be able to rotate quickly and freely Gradually stop. If the rotating parts are not rotating, indicating internal corrosion or deformation, do not buy.

Eight, to see whether the missing parts assembly. Regular assembly components must be complete and intact, in order to ensure smooth assembly and normal operation. Some assembly components on the individual small parts missing, will make the assembly parts can not work or even scrapped.