Stihl MS 251 Instruction Manual - Page 34
Leakage Test, 6.2.1 Preparations, 855 4201 on cylinder
View all Stihl MS 251 manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 34 highlights
2310RA072 TG 2310RA074 TG 6.2 Leakage Test Defective oil seals and gaskets or cracks in castings are the usual causes of leaks. Such faults allow supplementary air to enter the engine and upset the fuel-air mixture. This makes adjustment of the prescribed idle speed difficult, if not impossible. Moreover, the transition from idle speed to part or full throttle is not smooth. Always perform the vacuum test first and then the pressure test. The engine can be checked thoroughly for leaks with the pump 0000 850 1300. 6.2.1 Preparations : Fit the spark plug (1) and tighten it down firmly. - Remove the muffler and gasket, b 6.1 1 2 2 : Fit the test flange (1) 5910 855 4201 on cylinder exhaust port. : Fit the screws (2) - do not tighten down yet. 1 2 3 3 : Fit the sealing plate (1) 0000 855 8106 between the cylinder exhaust port and flange (2). : Tighten the screws (3) moderately. The sealing plate must completely fill the space between the two screws. - Remove the carburetor, b 12.5 - Remove the shroud, b 6.4 c 1 1 b - Pull off the boot and unscrew the spark plug. Flange (1) 4224 893 2501 can be modified as shown. a = 13 mm b = 39.25 mm c = 6 mm - Set the piston to top dead center. This can be checked through the spark plug hole. : Make sure the washer (1) is in place. 2310RA079 TG a 2710RA164 TG 2310RA073 TG MS 231, MS 231 C, MS 251, MS 251 C 33