Manual Primer Button - Mercury 40 Service Manual

Manual Primer Button

The manual starting primer bulb is designed to pro-
vide a rich fuel mixture to the engine during cold start
conditions. When the primer bulb is pressed in, fuel
is forced from the primer bulb into the intake manifold
via hose and fitting on the side of the manifold. When
the primer bulb is released, a suction is created in the
bulb and fuel is drawn into the bulb through a hose
from the carburetor float bowl.
PRIMER BUTTON FUEL FLOW DIAGRAM
b
a
c
e
a - Primer Cover
b - Primer Check Valve
c - Primer Button
d - Starter Handle Rest
e - Carburetor (3)
f - Intake Manifold
3B-20 - FUEL SYSTEM
d
CAUTION
All safety precautions should be adhered to
when testing the primer bulb system. Fuel
should be directed into suitable container and all
flammable materials extinguished and sources
of spark turned off.
PRIMER BUTTON TEST
Removing the primer hose from the intake manifold
and pressing the primer bulb will determine if the
primer is working properly as fuel should be expelled
from the hose whenever the primer bulb is pressed.
f
90-852572R1 JANUARY 1998