Mariner 100, Руководство по обслуживанию, Страница: 100 / 391

3A-13 90-13645--2 495 FUEL SYSTEM AND CARBURETION
PROBLEM 1: ENGINE IDLES ROUGH AND
STALLS
PROBLEM 2: ENGINE RUNS UNEVEN OR
SURGES
PROBLEM 3: ENGINE WILL NOT ACCELERATE
Possible Cause Corrective Action
Fuel tank air vent closed
or restricted. Check - Air vent must
be open all-the-way and
free from restrictions.
A pinched, cut or
restricted fuel line; also
loose fuel line
connection. Check all fuel lines and
replace as needed.
Check and tighten all
fuel line connections.
A dirty or restricted fuel
filter. Check, replace, or clean
all fuel filters.
Restricted filter in fuel
tank. Clean by rinsing in
clean lead-free gasoline
or kerosene.
Improperly mixed fuel;
contaminants (water,
dirt, etc.) in fuel. Check fuel and replace,
if necessary.
An inlet needle (in
carburetor) 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
carburetor.) Remove and replace
with new inlet needle.
Incorrect idle mixture
adjustment. Re-adjust.
Damaged fuel pump
diaphragm. Replace.
Carburetor is loose. Tighten bolts securely.
Chamber cover leaking
air. Tighten or replace
gasket.
Off idle holes plugged. Blow out with
compressed air.
Main nozzle or idle
nozzle air bleed holes
plugged. Blow out with
compressed air.
Improper main jet or
restricted jet. Clean or replace with
proper jet (refer to “Main
Jet Chart”).
Damaged reed(s). Inspect reeds as
outlined in Section 4A.
A crack in the fuel
pick-up outlet tube
(located in fuel tank). Replace.
A crack in the fuel outlet
tube (located in fuel
tank.) Replace.
Anti-Siphon valve
restricting fuel flow. Refer to “Checking for
Restricted Fuel Flow
Caused by Anti-Siphon
Valves,” following.
PROBLEM: FUEL BLOW-BACK OUT OF
CARBURETOR
Possible Cause Corrective Action
Chipped/Broken
(reed-block) Reeds Replace Reeds.
PROBLEM: ROUGH IDLE
If related to reed-block,
indicates excessive
preload in reeds. Replace Reeds.
PROBLEM: CAN’T REDUCE ENGINE RPM TO
SLOW IDLE
Multiple Chipped Reeds. Replace Reeds.
Checking for Restricted Fuel Flow
Caused by Anti-Siphon Valves
While anti-siphon valves are helpful from a safety
standpoint, they clog, they may be too small, or they
may have too heavy a spring. The pressure drop
across these valves can, create operational problems
and/or powerhead damage by restricting fuel. Some
symptoms of restricted (lean) fuel flow, are:
1. Loss of fuel pump pressure
2. Loss of power
3. High speed surging
4. Preignition/detonation (piston dome erosion)
5. Outboard cuts out or hesitates upon acceleration
6. Outboard runs rough
7. Outboard quits and cannot be restarted
8. Outboard will not start
9. Vapor lock
Any type of anti-siphon device must be located be-
tween the outboard fuel inlet and fuel tank outlet. A
method of checking [if such a device (or bad fuel) is
a problem source] is to operate the outboard with a
separate fuel supply which is known to be good.
If, it is found that the anti-siphon valve is the cause of
the problem, either 1) replace the anti-siphon valve or
2) replace it with a solenoid-operated fuel shutoff
valve.