This is the part that often needs replacing when you let go of gun and the pressure washer keeps stop starting.
When undoing head keep motor to bottom or oil will come out.
It is recommended to replace the non-return valve also, but not always required. Part number 127440082
Suits:
C120.3
C120.5
C125.3
C125.4
C130.1
C130.2
C135.1
E120.1