Mercury 90 Service Manual

3B-24 - FUEL SYSTEM 90-830234R3 DECEMBER 1997
Enrichener System
Description for Three Cylinder
Engines
1995 and Earlier – Fuel flows (gravity fed) from top
carburetor float bowl to fuel enrichment valve.
1996/1997/1998 – Enrichener is pressurized by fuel
from a T-fitting in the fuel hose between the top and
middle carburetors.
Valve is electrically opened when key is turned to the
“ON” position and pushed in (and held in). Fuel is
supplied to engine through fittings located in the top,
middle, and bottom carburetors. Valve returns to the
closed position when key (or choke button) is re-
leased. Valve can be operated manually by PRESS-
ING and HOLDING button located at bottom of valve.
Enrichener Valve Hose Installation -
Three Cylinder Engines
a
b
c
I.D. 0.125 – 1996
I.D. 0.156 – 1996
a-94/95 Models – Connect to Fitting on Side of Carburetor
96/97/98 Models – Connect to Fitting between Top and
Middle Carburetors
b - Electrical Harness
c - Enrichener Valve Manual Operation Button
Description for Four Cylinder Engines
Enrichener valve receives fuel from a T-fitting be-
tween #1 and #2 carburetors. Valve is electrically
opened when ignition key is turned to the “ON” posi-
tion and pushed in (and held in). Fuel is dispensed to
T-fittings on intake manifold of cylinders #2 and #4.
Internal passages route fuel from cylinders #2 and #4
to cylinders #1 and #3. Valve returns to the closed
position when key (or choke button) is released.
Valve can be operated manually by PRESSING and
HOLDING button located on top of valve.
Enrichener Valve Hose Installation -
Four Cylinder Engines
23121
c
b
a
I.D. 0.156 – 1996
I.D. 0.125 – 1996
a - Enrichener Valve Manual Operation Button
b - Electrical Harness
c - Connect to Fitting between #1 and #2 Carburetors

Mercury 90 Specifications

General

Brand	Mercury
Model	90
Category	Outboard Motor
Language	English