Trouble Shooting When The Engine Fails To Start - O.S. engine MAX-75AX-BE Instruction Manual

Four key points
For quick, reliable starting, the following four conditions are required.
1 Good compression. 2 Adequate "glow" at glowplug.
4 Sufficient electric starter rotating speed.
If the engine fails to start, or does not keep running after being started, check symptoms against the
following chart and take necessary corrective action.
Note: The most common causes of trouble are marked with three asterisks, the less common problems
with one or two asterisks.
Symptom Factor
1 Sluggish rotation
Engine fails
to fire.
Glowplug battery
discharged.
2
Glowplug element is
burned out
Something wrong with
battery leads.
Engine "flooded" due to
excessive priming.
3
Insufficient priming.
Symptom Factor
2 Incorrect heating of
Engine fires
glowplug.
intermittently but
3 Over priming.
does not run.
1
Sluggish rotation.
2
Glowplug battery
Engine fires once
discharged.
or twice, then
fails to fire.
3
Insufficient priming.
Engine starts but
rpm decreases 3
Mixture too rich.
and engine eventually
stops.
3
Fuel not reaching the
Engine starts,
engine.
rpm increases
and engine cuts
out.
3
Mixture too rich.
Engine stops when
the current to the
2
Deterioration of glowplug
glowplug is discon-
and/or fuel
nected after starting.

TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START

Cause
. . . . . .
Recharge the electric starter battery.
. . . . . .
Recharge lead-acid cell or replace dry battery. (Note: An unused, or almost
unused, dry battery may sometimes be of insufficient capacity if it is "old
stock".)
. . . . .
Replace glowplug. Check that applied voltage is not too high.
. . . .
Check glowplug heating using other leads.
. . . .
Close needle-valve fully and remove glowplug, then flip propeller to pump
out excess fuel. (Invert engine, if possible, while pumping out excess). Re-
start engine. (Priming is not necessary at this time.)
. . . . .
Repeat priming procedure referring to Priming.
34
Cause
. . . . .
Voltage too high or too low. Re-check and readjust referring to "BEFORE
STARTING" .
. . . . . . . .
Continue applying an electric starter. If the engine dos not start after more
than 4 tries, disconnect the current to the glowplug and leave for a few
minutes., then re-energize plug and apply starter. If the engine still does not
start, remove glowplug and pump out excess fuel by applying the starter.
. . . . . .
Then re-start. (Priming is not necessary.)
Recharge the electric starter battery.
. . . . . .
Recharge lead-acid cell or replace dry battery.
(Note: An unused, or almost unused, dry battery may sometimes be of
insufficient capacity if it is "old stock".)
. . . . .
Repeat priming procedure referring to Priming.
. . . . . . .
Close needle-valve half turn (180 ) and wait for several minutes then re-
start.(Priming is not necessary.)
. . . . .
Make sure that tank is filled with fuel. Check that there is not something
wrong with the fuel line (kinked or split). Check that carburettor is not
clogged with dirt.
. . . . . . .
Close the needle-valve a little before disconnecting current to the glowplug.
. . .
Change fuel or glowplug.
35
3 Correct mixture.
Corrective action
Corrective action