Yanmar 3JH4E Service Manual page 151

(4) Valve contact/mounting
Clean the valve seat and valve with air to remove any
foreign matter.
(5) Inspect the diaphragm spring and piston
spring for settling and the piston for wear,
and replace as necessary.
NOTE: Replace parts as an assembly.
6. FUEL INJECTION EQUIPMENT
Inlet valve
135
Outlet valve