Piper Navajo PA-31 Service Manual page 514

PIPER NAVAJO SERVICE MANUAL
TABLE VIII-II.
Trouble
Failure of Engine to start.
TROUBLESHOOTING CHART
Cause
Lack of fuel.
Overpriming.
Insufficient prime.
Incorrect throttle setting.
Defective spark plugs.
Defective ignition wire.
Defective battery.
Improper operation of
magneto breaker.
Mag impulse coupling not
operating properly.
Mag impulse coupling
magnetized.
Mag retard contact not
operating electrically.
Inoperative or defective
vibrator.
Magneto timing incorrect.
Lack of sufficient fuel flow.
Internal failure.
(ENGINE)
Remedy
Check fuel system for leaks.
Fill fuel tank. Clean dirty lines,
strainers or fuel valves.
Open throttle and "unload"
engine by engaging starter.
Mixture in Idle Cut-Off.
Increase prime (insure that
primer is not leaking).
Open throttle to one-fourth
of its range.
Clean and adjust or replace
spark plugs.
Check with electric tester and
replace any defective wires.
Replace with charged battery.
Clean points. Check timing
of magnetos.
Remove and check for binding
or broken impulse spring.
Remove, de-magnetize or
replace impulse coupling.
Check all connections at
switch and vibrator. Adjust
retard points.
Check and replace vibrator,
if necessary.
Time magneto.
Disconnect fuel line at fuel
injector and check fuel flow.
Check oil screens for metal
particles. If found, complete
overhaul of engine may be
indicated.
Revised: 9/24/81
POWER PLANT
2J16