Piper Navajo PA-31 Service Manual page 517

Carburetor heat door not
rigged properly.
PIPER NAVAJO SERVICE MANUAL
TABLE VIII-II. TROUBLESHOOTING CHART (ENGINE) (cont.)
Trouble
Cause
Remedy
Engine will not turn static
(ground runup) RPM.
Restriction in induction air
system, incorrect or improperly
installed airbox.
Inspect and remove restriction.
Injector too rich or too lean.
Prop out of adjustment,
low pitch.
Crankshaft to camshaft
timing off.
Exhaust muffler internal
baffles broken and blocking
exhaust outlet.
Replace, recalibrate or over-
haul injector.
Adjust for full travel.
Remove accessory housing and
time correctly.
Remove, inspect thoroughly
and replace if necessary.
NOTE
If broken baffles are free to move around in muffler, engine may
function properly sometimes although at other times it may not.
Excessively dirty air filter.
Replace.
Rig so that door goes from full
open to full closed.
NOTE
Insure that engine vibrations are not keeping carburetor heat door
open slightly. Tape shut (for test only) if necessary.
Incorrect magneto to engine
timing.
Fouled spark plugs.
Incorrect tach reading.
Check and adjust as
necessary.
Remove, clean or replace as
necessary.
Repair or replace tachometer.
Engine surges.
Injector nozzles dirty.
Remove and clean.
Faulty or improper governor.
Replace.
Added: 9/24/81
POWER PLANT
2J19