O.S. Engines 21XM - Manual (Page 16)

4
2
3
Symptom Factor Cause Corrective action
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, Apply starter to pump out excess fuel. Re-start
engine.
Refer to p.9
Sluggish rotation
Glowplug battery
discharged.
Glowplug element is
burned out
Something wrong with
battery leads.
Engine "flooded"
Insufficient fuel.
★
★★
★
★
★★
★
Engine fails
to fire.
Four key points
For quick, reliable starting, the following four conditions are required.
1 Good compression. 2 Adequate "glow" at glowplug. 3 Correct mixture. 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.
. . . . .
. . . . .
. . . .
. . .
. . . . . .
. . . . . .
2
3
2
4
3
3
3
3
2
Voltage too high or too low. Re-check and readjust referring to "BEFORE STARTING"
Continue to apply starter. If necessary disconnect battery from glowplug and leave for a few
minutes, then re-energize plug. If engine still does not start, remove glowplug and pump out excess
fuel.
Then re-start.
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".)
Refer to p.9
Close needle-valve half turn (180˚) and wait for several minutes, then re-start.
Make sure that tank is filled with fuel. Check that there is not something wrong with fuel tubing
(kinked or split). Check that carburettor is not clogged with dirt.
Close the needle-valve a little.
Change fuel or glowplug.
Incorrect heating of
glowplug.
Excess fuel
Sluggish rotation.
Glowplug battery
discharged.
Insufficient fuel
Mixture too rich.
Fuel not reaching the
engine.
Mixture too rich.
Mismatch of glow plug
and fuel.
★★
★★
★
★★
★★
★★★
★
★★
★
Engine fires
intermittently but
does not run.
Engine fires once or
twice, then fails to fire.
Engine starts but revol-
utions decrease and en-
gine eventually stops.
Engine starts, then
revolutions increase
and engine cuts out.
Engine stops when battery
leads are disconnected
after starting.
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TROUBLE SHOOTING WHEN THE ENGINE FAILS TO START
15