Mercury 45 Jet 50-55 Service Manual page 94

PROBLEM: ENGINE FLOODS
Possible Cause
Dirt or foreign particles
are preventing inlet
needle from seating.
Worn inlet needle.
Punctured float.
Incorrect float setting.
PROBLEM: ENGINE RUNS TOO LEAN
Possible Cause
Carburetor is loose. Air
leaks past mixing
chamber cover.
Fuel level too low.
Clogged high speed jet.
Restricted fuel flow to
carburetor.
Incorrect high speed jet.
Idle mixture set too lean.
Air leakage into fuel sys-
tem.
Anti-Siphon valve re-
stricting fuel flow.
PROBLEM: ENGINE RUNS TOO RICH
Possible Cause
Fuel level too high.
Carburetor floods.
Idle nozzle air
holes plugged.
Restricted air flow.
Main Fuel Jet loose.
90-817643R1 DECEMBER 1996
Corrective Action
Flush out inlet seat and
clean inlet needle.
Replace.
Replace.
Reset float.
Corrective Action
Tighten bolts securely.
Tighten cover or re-
place gasket.
Reset float level.
Check and clean.
Check fuel lines and fil-
ter(s) for restricted
flow.
Refer to main jet chart
and replace with prop-
er jet.
Adjust to run richer.
Check fuel line connec-
tions, hose clamps,
fuel pump, and fuel
outlet tube (located in
fuel tank) for loose fit-
tings.
Refer to "Checking for re-
stricted fuel flow
caused by Anti-Siphon
valves."
Corrective Action
Reset float to correct
level.
See preceding "Engine
Floods"
Blow out with com-
pressed air.
Check cowl air inlet and
carburetor for obstruc-
tions.
Retighten Jet.
PROBLEM 1: ENGINE IDLES ROUGH AND
STALLS
PROBLEM 2: ENGINE RUNS UNEVEN OR
SURGES
PROBLEM 3: ENGINE WILL NOT ACCELERATE
Possible Cause
Fuel tank air vent closed
or restricted.
A pinched, cut or re-
stricted fuel line; also
loose fuel line connec-
tion.
A dirty or restricted fuel
filter.
Restricted filter in fuel
tank.
Improperly mixed fuel;
contaminants (water,
dirt, etc,) in fuel.
An inlet needle (in carbu-
retor) that is either
stuck open or closed.
(A needle, that is stuck
open, will cause a
flooding condition. A
needle, that is stuck
closed, will prevent
fuel from entering car-
buretor.)
Incorrect idle mixture ad-
justment.
Damaged fuel pump dia-
phragm.
Carburetor is loose.
Chamber cover leaking
air.
Off idle holes plugged.
Main nozzle or idle
nozzle air bleed holes
plugged.
Improper main jet or re-
stricted jet.
Damaged reed(s).
A crack in the fuel pick-
up outlet tube (located
in fuel tank).
Corrective Action
Check - Air vent must be
open all-the-way and
free from restrictions.
Check all fuel lines and
replace as needed.
Check and tighten all
fuel line connections.
Check, replace, or clean
all fuel filters.
Clean by rinsing in clean
lead-free gasoline or
kerosene.
Check fuel and replace,
if necessary.
Remove and replace
with new inlet needle.
Re-adjust.
Replace.
Tighten bolts securely.
Tighten or replace gas-
ket.
Blow out with com-
pressed air.
Blow out with com-
pressed air.
Clean or replace with
proper jet (refer to
"Main Jet Chart").
Inspect reeds as outlined
in Section 4A.
Replace.
FUEL SYSTEMS - 3A-9