Mariner 80 - Carburetion; Fuel System Troubleshooting

3A-12 90-13645--2 495FUEL SYSTEM AND CARBURETION
Carburetion
Fuel System Troubleshooting
Troubles, that are caused by items 1-thru-5, listed be-
low, may give the impression that a problem exists in
the fuel system:
1. Spark plugs
2. Ignition spark voltage
3. Cylinder compression
4. Reed valves
5. Ignition timing
Troubleshooting Charts
PROBLEM 1: ENGINE TURNS OVER BUT WILL NOT
START OR STARTS HARD WHEN
COLD
Possible Cause Corrective Action
Improper starting
procedure.
Check procedure, as
outlined in “Operation
and Maintenance
Manual.”
Fuel tank empty;
improperly mixed fuel;
contaminants (water,
dirt, etc.) in fuel.
Check fuel in fuel tank
and replace or add.
Fuel tank air vent closed
or restricted.
Air vent must be open
and free from
contaminants.
A pinched or restricted
fuel line.
Check, and replace as
needed.
Dirty or restricted fuel
filter.
Check, replace or clean.
Enrichener valve not
operating.
Check enrichener
system. (Refer to
“Enrichener System”
following.)
An inlet needle (in
carburetor) that is stuck
open or closed. (A
needle stuck open, will
cause a flooding
condition. A needle stuck
closed, will prevent fuel
from entering carburetor.)
Remove, clean, or
replace.
Anti-Siphon valve
restricting fuel flow.
Refer to “Checking for
Restricted Fuel Flow
caused by Anti-Siphon
Valves”, following.
See “Checking for Restricted Fuel Flow caused
by Anti-Siphon Valves”, page 3A-1.
PROBLEM: ENGINE FLOODS
Possible Cause Corrective Action
Dirt or foreign particles
are preventing inlet
needle from seating.
Flush out inlet seat and
clean inlet needle.
Worn inlet needle. Replace.
Punctured float. Replace.
Incorrect float setting. Reset float.
PROBLEM: ENGINE RUNS TOO LEAN
Possible Cause Corrective Action
Carburetor is loose. Air
leaks past mixing
chamber cover.
Tighten bolts securely.
Tighten cover or replace
gasket.
Fuel level too low. Reset float level.
Clogged high speed jet. Check and clean.
Restricted fuel flow to
carburetor.
Check fuel lines and
filter(s) for restricted
flow.
Incorrect high speed jet. Refer to main jet chart
and replace with proper
jet.
Idle mixture set too
lean.
Adjust to run richener.
Air leakage into fuel
system.
Check fuel line
connections, hose
clamps, fuel pump, and
fuel outlet tube (located
in fuel tank) for loose
fittings.
Anti-Siphon valve
restricting fuel flow.
Refer to “Checking for
restricted fuel flow
caused by Anti-Siphon
valves.”
PROBLEM: ENGINE RUNS TOO RICH
Possible Cause Corrective Action
Fuel level too high. Reset float to correct
level.
Carburetor floods. See preceding “Engine
Floods”
Idle nozzle air holes
plugged.
Blow out with
compressed air.
Restricted air flow. Check cowl air inlet and
carburetor for
obstructions.
Main Fuel Jet loose. Retighten Jet.