Yanmar 3YM30 Service Manual page 167

(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.
Inlet valve
146R1
6. Fuel injection equipment
Outlet valve
001568-00E