Mercury Optimax Models 135, 150, Direct Fuel Injection., Page 181Get this manual
DIRECT FUEL INJECTION
NOTE: It is recommended that direct injectors remain in the cylinder head (if they are not to be replaced) while removing the fuel railThe direct injectors have teflon seal which may expand if the injector is removed from the headThis expansion may cause reinstallation difficulty or require the replacement of the seal4Remove nuts securing fuel rail5As fuel rail is removed, use flat tip screw driver to hold direct injectors in cylinder head
aFuel RailDirect Injectors
Fuel Rail Disassembly