Trouble shooting the Outboard motor


NOTE: When trouble-shooting power heads of 4-cycle outboard motors, follow procedures outlined for inboard engines.



1. Manual starter rope pulls out,  but pawls do not engage.
  A. Friction spring bent or burred.
  B. Excess grease on pawls or spring.
       (too heavy of a grease used?)
  C. Pawls bent or burred.

2. Starter rope does not return.
A. Recoil spring broken or binding.
      (too heavy of a grease used?)
B. Starter housing bent.
C. Loose or missing parts.

3. Clattering manual starter.
A. Friction spring bent or burred.
B. Starter housing bent.
C. Excess grease on pawls or spring.
D. Dry starter spindle.
E. Just plum worn out...

4. Electric starter inoperative.
A,  Loose or corroded connections or ground.
B.  Starting circuit safety switch open, or out of adjustment.
C.  Improper capacity or weak battery or corroded battery terminals
D.  Faulty starter solenoid.
E.  Moisture in electric starter motor.
F.  Broken or worn brushes in starter motor.
G.  Faulty fields.
H.  Faulty armature.
I.  Broken wire in harness or connector
J.  Faulty starter key, push button or safety switch.
K.  Worn or frayed insulation.

5. Electric starter does not engage but solenoid clicks.
  A. Loose or corroded connections or ground.
  B. Weak battery.
  C. Faulty starter solenoid.
  D. Broken wire in electric harness.
  E. Loose or stripped post on starter motor.
  F. See steps in number 4.
  G. Bendix shaft rusted or bendix clutch broken

6. Hard to start or won't start.
A. Empty gas tank.
B. Gas tank air vent not open.
C. Fuel lines kinked or severely pinched.
D. Water or dirt in fuel system
E. Clogged fuel filter or screens.
F. Motor not being choked to start.
G. Engine not primed -- pump primer system.
H. Carburetor adjustments too lean (not allowing enough fuel to
    start engine).
I. Timing and synchronizing out of adjustment.
J. Manual choke linkage bent -- auto choke out of adjustment.
K. Spark plugs improperly gapped, dirty or broken.
L. Fuel tank primer inoperative (pressurized system).
M. Ignition points improperly gapped, burned or dirty or triggering
    (CD) system inoperative.
N. Loose, broken wire or frayed insulation in electrical system.
O. Reed valves not seating or stuck shut.
P. Weak coil or condenser.
Q.  Faulty gaskets.
R.  Cracked distributor cap or rotor or shorted rotor.
S.  Loose fuel connector.
T.  Amplifier (CD) inoperative.
U.  Poor engine or ignition ground.
V.  Faulty ignition or safety switch.
W. Low cranking speed.
X. Low voltage to ignition, when cranking.

7. Low speed miss or motor  won't idle smoothly and slowly  enough.
A.  Improper fuel/oil mixture.
      (very old gas?)
B.  Timing and synchronizing out of adjustment.
       (linkage fell off?)
C.  Carburetor idle adjustment (mixture lean or rich).
D.  Ignition points improper (gap, worn or fouled) or
       triggering (CD) system inoperative.
E.  Weak coil or condenser.
       (only way to know for sure... Replace it)
F.  Loose or broken ignition wires.
G. Loose or worn magneto plate.
H. Spark plugs (improper gap or dirty incorrect plug).
      (don't waste time try a new set)
I.  Head gasket, reed plate gasket (blown or leaking).
J.  Reed valve standing open or stuck shut.
K.  Plugged crankcase bleeder, check valves, or lines.
L.  Leaking crankcase halves.
M. Leaking crankcase seals (top or bottom).
N.  Exhaust gases returning thru intake manifold.
        (cowling seals missing or damaged)
O.  Poor distributor ground.
        (look for a grounding wire or add one)
P.  Cracked or shorted distributor cap or rotor.
Q.  Fuel pump diaphragm punctured.
       (check spark plugs, usually one will be running very rich)
R. Accessory tachometer shorted or not compatible
    with ignition system.
S. Faulty ignition or safety switch.

8. High speed miss or intermittent  spark.
  A. Spark plugs improperly gapped or dirty.
  B.  Loose, leaking or broken ignition wires.
  C.  Breaker points (improper gap or dirty. worn cam or cam
        follower) or triggering (CD) system faulty.
  D.  Weak coil or condenser
  E.  Water in fuel.
  F.  Leaking head gasket or exhaust cover gasket.
  G.  Incorrect spark plug
  H.  Engine improperly timed.
  I.  Carbon or fouled combustion chambers.
  J.  Magneto, distributor, or CD triggering system poorly grounded.
  K.  Distributor oiler wick bad.
        (points are hopping)
  L.  Accessory tachometer shorted or not compatible with
        ignition system.
  M.  Faulty ignition or safety switch.

9. Coughs, spits, slows.
  A.  Idle or high speed needles set too lean.
  B.  Carburetor not synchronized.
  C.  Leaking gaskets in induction system.
  D.  Obstructed fuel passages.
  E.  Float level set too low.
  F.  Improperly seated or broken reeds.
  G.  Fuel pump pressure line ruptured.
  H.  Fuel pump (punctured diaphragm), check valves stuck open or
        closed, fuel lines leak.
  I.  Poor fuel tank pressure (pressurized system).
  J.  Worn or leaking fuel connector.

10. Vibrates excessively or runs   rough and smokes.
  A. Idle or high speed needles set too rich.
  B. Too much oil mixed with gas.
  C. Carburetor not synchronized with ignition properly.
  D. Choke not opening properly.
  E. Float level too high.
  F. Air passage to carburetor obstructed.
  G. Bleeder valves or passages plugged.
  H. Transom bracket clamps loose on transom.
  I. Prop out of balance.
  J. Broken motor mount.
  K. Exhaust gases getting inside motor cover.
  L. Poor ignition -- see steps in number 8.
  M. Motor too low in water.
        (excessive exhaust back-pressure)

(Continued on page 187)

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