End worm screw oil pump chainsaw compatible EFCO EMAK OLEO-MAC For models: EFCO 136 , 136 S , 137 , 140 , 141 S , MT 3700 , MT 4000 , MT 4100 S OLEO-MAC EMAK 936 , 937 , 940 , 941C , GS370 , GS410 , GS940 Part no.: 40271969 Original part no.: 50050025 EFCO NS