Fuel Rail; Fuel Pressure Regulator - Mercury 200 OptiMax Jet Drive Service Manual

Hose Clamp Tool Kit

Fuel Rail

Fuel Pressure Regulator

The fuel regulator is located on the port fuel rail.
The fuel pump can deliver pressure in excess of 689.5 kPa (100 psi). Fuel pressure inside the fuel rail must be at a specific higher
pressure over the air pressure or the PCM calibrations will be incorrect. The fuel pressure regulator maintains the higher pressure
over the air pressure in the fuel rail and allows the excess fuel to return into the vapor separator. The fuel pressure regulator
diaphragm is held closed with a spring that requires a specific pressure to force the diaphragm off the diaphragm seat. The backside
of the diaphragm is exposed to air rail pressure. As the air rail pressure increases, the fuel pressure needed to open the regulator
will equally increase.
90-8M0050731 MAY 2011
Direct Fuel Injection
91‑803146A04
16101
Page 3B-49