Zündmagnet Slick 4000/6000
• Schwerer Start
• Propeller schlägt zurück während des Starts
• Rauer Lauf
• Rauer Lauf oder Vibration in einem bestimmten Drehzahlbereich
• Sehr starker Magnetabfall während des Magnet Checks
• Zündmagnet gibt keinen Funken ab
• Zündmagnet “Heiß” (Hot Magneto)
• Stromausfall
• Montageflansch gebrochen
• Zündkontakte sind stark abgebrannt
• Hochspannungslippe der Zündspule ist abgenutzt oder zeigt Abbrand
• Zündspule gerissen oder Lichtbögen in Gehäuse
• Verteilerfinger des Verteilerrads lose
• Elektrodenstifte der Verteilerkappe ausgekerbt oder stark verbrannt
• Verteilerkohle extrem verschlissen
• Bearing bar burned
• Defektes Lager (lose/unrund/ausgelaufen)
• Alle Zündmagnete: Verschmutzung und Korrosion 
• Speziell druckbelüftete Zündmagnete: Verschmutzung und Korrosion


Zündmagnet Bendix S-20/200
• Schwerer Start
• Triebwerk läuft rau
• Magneto Drop-off Check Out of Limits

Zündmagnet Bendix S-1200
• Schwerer Start
• Triebwerk läuft rau
• Magneto Drop-off Check Out of Limits

Zündmagnet Bendix D-3000
• Schwerer Start
• Triebwerk läuft rau
• Magneto Drop-off Check Out of Limits
• Störungen im Funk

Schwerer Start
1. Incorrect external timing to engine
    Consult engine manufactures specification for ignition timing.
    Correct as required.

2. Incorrect internal timing
    Consult Unison Manual L-1363, Section 7.10 for internal timing specifications.
    Correct as required.

3. Point gap setting incorrect
    Consult Unison Manual L-1363, Section 7.10 for point gap specifications.
    Correct as required.

4. Faulty impulse coupling
    Consult Unison Manual L-1363, Section 3.3.4, for impulse coupling specifications and
    Inspection procedures.

5. Overtorqued impulse coupling nut
    Torque nut to 120-320 in-Ibs on magnetos with attached drive gears. There must be
    .010 to .020” play between drive gear and impulse coupling.
    Correct as necessary.

6. Worn pawls or stop pin
    Inspect pawls and stop pin for wear. Correct as necessary.

7. Impulse coupling fails to return to unwound position
    Inspect impulse coupling nut for torque.

8. Fouled Spar plugs
    Clean spark plugs according to manufacturer’s specification.

9. Incorrect spark plug gap
    Re-gap spark plug to manufacturer’s specifications.

10. Faulty ignition switch
    Inspect ignition switch for possibility of intermittent grounding and proper operation.
    Repair or replace as necessary.

11. Corrosion on harness lead contacts
    Consult manual L-1177 for proper cleaning and inspection procedures.
    Correct as required.

12. Magneto Internal Component Failure:
    Consult Unison Manual L-1363, Section 3, for specifications and inspection procedures.
a. Points
    Inspect for excessive burning, pitting, corrosion gap setting and general operation.
    Replace as necessary.
b. Cam
    Inspect cam for excessive wear or unevenness that could cause “point spread”.
    Correct as necessary.
c. Condenser
    Inspect for faulty P-lead connection, P-lead stud for over-torqued condition, damaged pigtail
    connector and damaged grounding Replace as necessary.
d. Coil
    Inspect for cracks, damage to high tension strap pr pigtail connector and integrity of windings.
    Replace as necessary.
e. Distributor gear
    Inspect electrode finger for looseness, gear teeth, shaft. Inspect carbon brush for damage.
    Replace as necessary.
f. Distributor Block
    Inspect distributor towers for evidence of abrasion or excessive burning.
    Examine rotor gear bushings for wear. Replace as necessary.

13. Incorrect or nonstandard starting procedures
    Consult engine manufactures operation manual for proper operation and performance.
    Correct as required.

14. Faulty fuel delivery system
    Consult engine manufacturer’s manual for specifications and operation.
    Correct as required.

15. Inoperative retard contact point circuit
    Inspect wiring connections and operation of points. Correct as required.

Propeller schlägt zurück während des Starts

1. Impulse coupling not staying engaged while starter engaged     Inspect impulse coupling for operation. Correct as required.

2. Inoperative retard contact point circuit     Inspect for faulty wiring, timing, or inoperative contact points.    Correct as required.

3. Non-impulse magneto not grounded while starter engaged     Inspect and correct as required.

Rauer Lauf
1. Incorrect external timing to engine
    Consult engine manufacturer’s manual for specifications of ignition timing.
    Correct as required

2. Incorrect internal timing
    Consult Unison Manual L-1363, Section 7.10, for internal timing specifications.
    Correct as required.

3. Fouled spark plugs
    Clean spark plugs according to manufacturer’s specifications.

4. Incorrect spark plug gap
    Regap spark plug to manufacturer’s specifications.

5. Faulty spark plug
    Test spark plug according to manufacturer’s specifications.

6. Faulty ignition lead
    Consult Unison Harness Maintenance Manual L-1499, for ignition lead troubleshooting information.

7. Faulty ignition switch
    Inspect ignition switch for possibility of intermittent grounding and proper operation.
    Repair of replace as necessary.

8. Magneto Internal Component Failure:
    Consult Unison Manual L-1363, Section 3, for specifications and inspection procedures
a. Points
    Inspect for excessive burning, pitting,corrosion, gap setting and general operation.
    Replace as necessary.
b. Cam
    Inspect cam for excessive wear or unevenness that could cause “cam spread”.
    Correct as necessary.
c. Condenser
    Inspect for faulty P-Lead connection, P-lead stud for overtorqued condition,
    damaged pigtail connector and damaged grounding. Replace as necessary.
d. Coil
    Inspect for cracks, damage to high tension strap or pigtail connector and integrity of windings.
    Replace as necessary.
e. Distributor Gear
    Inspect electrode finger for looseness, gear teeth, shaft. Inspect carbon brush for damage.
    Replace as necessary.
f. Distributor Block
    Inspect distributor towers for evidence of abrasion or excessive burning.
    Examine rotor gear bushings for wear. Replace as necessary.

9. Excessive heat.
    Inspect baffling or cooling air duct. Correct as necessary.

10. Faulty fuel delivery system.
    Consult engine manufacturer’s operations manual for proper operation and performance.
    Correct as required.

11. Faulty induction system
    Inspect for leaks and faulty valve operation. Consult engine manufacturer’s
    specifications for proper operation and performance.

12. Faulty exhaust system.
    Inspect for obstructions in exhaust pipes and mufflers, faulty valve operation.
    Consult engine manufacturer’s specification for proper operation and performance.

Rauher Lauf oder Vibration in einem bestimmten Drehzahlbereich
1. Propeller out of track or unbalanced
    Consult propeller manufacturer’s manual for specifications.
    Correct as necessary.

2. Propeller imbalanced or installed incorrectly
Correct as necessary

3. Propeller/Engine harmonic resonance
    Consult airframe manufacturer’s operations manual .
    Correct as necessary.

4. Magneto Internal Component Failure
    Consult Unison Manual L-1363, Section 3 for specifications and inspections procedures.

a. Points
Inspect for excessive burning, pitting, corrosion, gap setting and general operation.
Replace as necessary.

b. Cam
Inspect cam for excessive wear or unevenness that could cause “cam spread”.
Correct as necessary.

c. Condenser
    Inspect for faulty P-lead connection, P-lead stud for overtorqued condition,
    damaged pigtail connector and damaged grounding. Replace as necessary.

d. Coil
    Inspect for cracks, damage to high tension strap or pigtail connector and integrity of windings.
    Replace as necessary.

e. Distributor Gear
    Inspect electrode finger for looseness, gear teeth, shaft. Inspect carbon brush for damage.
    Replace as necessary.

f. Distributor Block
    Inspect distributor towers for evidence of abrasion or excessive burning.
    Examine rotor gear bushings for wear. Replace as necessary.

5. Faulty fuel delivery system
    Consult engine manufacturer’s manual for specifications and operation. Correct as required.

6. Faulty induction system
    Inspect for leaks and faulty valve operation. Consult engine manufacturer’s specifications
    for proper operation and performance. Correct as required.

7. Faulty exhaust system
    Inspect for obstructions in exhaust pipes and mufflers, faulty valve operation.
    Consult engine manufacturer’s specification for proper operation and performance.

Sehr starker Magnetabfall während des Magnet Checks
1. Incorrect external timing to engine
    Consult engine manufacturer’s manual for specifications of ignition timing. Correct as necessary.

2. Incorrect internal timing
    Consult Unison Manual L-1363, Section 7.10, for internal timing specifications. Correct as required.

3. Fouled spark plugs
    Clean spark plugs according to manufacturer’s specifications.

4. Incorrect spark plug gap
    Re-gap spark plug to manufacturer’s specifications.

5. Faulty spark plug
    Test spark plug according to manufacturer’s specifications.

6. Faulty tachometer
    Confirm tachometer accuracy at RPM where magneto drop noted. Correct as necessary.

7. Faulty ignition lead
    Consult Unison Harness Maintenance Manual L-1499 for ignition lead troubleshooting information.
    Correct as required.

8. Corrosion on harness lead contacts
    Consult Unison Harness Maintenance Manual L-1499 for proper cleaning and inspection procedures.
    Correct as required.

Zündmagnet gibt keinen Funken ab
1. Faulty ignition switch
    Inspect ignition switch for possibility of intermittent grounding and proper operation.
    Repair or replace as necessary.

2. Faulty condenser
    Consult Unison Manual L-1363, Section 3.3.7. Inspect for faulty P-lead connection,
    broken P-lead stud, damaged pigtail connector, and damaged grounding. Replace as necessary.

3. Point gap setting incorrect
    Consult Unison Manual L-1363, Section 7.10, for point cap specifications. Correct as required.

4. Retard contact point circuit inoperative
    Inspect and correct as required.

Zündmagnet “Heiß” (Hot Magneto)
1. Faulty ignition switch
    Inspect ignition switch for possibility of intermittent grounding and proper operation.
    Repair or replace as necessary.

2. Broken “P” lead
    wireRepair as necessary.

Stromausfall
1. Incorrect external timing to engine
    Consult engine manufacturer’s manual for specifications of ignition timing. Correct as required.

2. Faulty Tachometer
    Consult engine manufacturer’s manual for specifications of ignition timing. Correct as required.

Montageflansch gebrochen
1. Hold down clamp over torqued.
    Torque hold-down clamps to 190 – 220 in-Ibs.

2. Hold down clamps torqued unevenly.
    When magneto is reinstalled, be sure clamps are tightened with even pressure.

3. Magneto gasket residue on accessory case mounting pad.
    Be sure mounting face is free of gasket residue.

Zündkontakte sind stark abgebrannt
1. Faulty condenser
    Consult Unison Manual L-1363, Section 3.3.7, for testing procedure. Replace as necessary.

2. Improper spark plug gap
    Re-gap plugs according to manufacturer’s specifications.

3. Fouled spark plug
    Clean spark plug according to manufacturer’s specifications.

4. Excessive heat
    Inspect baffling or cooling air duct. Correct as necessary.

Hochspannungslippe der Zündspule ist abgenutzt oder zeigt Abbrand
1. Improper tension between high tension lead and carbon brush
    Consult Unison Manual L-1363, Section 7.7, for high tension lead loading specifications.

http://www.wmtonline.eu/magnetos_troubleshooting.php#back Zündspule gerissen oder Lichtbögen in Gehäuse
1. Faulty coil
    Consult Unison Manual L-1363, Section 3.3.5, for specifications and inspection procedures.
    Replace as necessary.

2. Improper spark plug gap
    Re-gap spark plug to manufacturer’s specifications.

3. Fouled spark plug
    Clean spark plug according to manufacturer’s specifications.

4. Faulty spark plug
    Inspect spark plug according to manufacturer’s specifications.

5. Excessive heat
    Inspect baffling or cooling air duct. Correct as necessary

Verteilerfinger des Verteilerrads lose
1. Timing pin wedged between electrode and distributor block during timing process.
    Consult Unison Manual L-1363 for proper timing procedures. Replace block and gear assembly.

Elektrodenstifte der Verteilerkappe ausgekerbt oder stark verbrannt
1. Electrode finger contacting towers
    Inspect and replace as necessary.

Verteilerkohle extrem verschlissen
1. Improper lubrication of bushing
    Consult Unison Manual L-1363, Section 3.3.8, for proper maintenance procedures.

Bearing bar burned
1. Carbon tracking due to excessive carbon brush wear
    Consult Unison Manual L-1363, Section 7.7, for high tension lead loading specifications.

Defektes Lager (lose/unrund/ausgelaufen)
1. Bearing not updated to correct configuration.
    Consult Unison Manual L-1363, Section 3.3.2 and 7.1, for proper maintenance procedure.
2. Improper bearing installation
    Consult Unison Manual L-1363, Section 3.3.2 and 7.1, for proper maintenance procedure.

Nur druckbelüftete Zündmagnete: Verschmutzung und Korrosion
1. Faulty pressurization or filtration system
    Consult engine manufacturer’s manual for pressurization system specifications.

Alle Zündmagnete: Verschmutzung und Korrosion
1. Excessive or improper solvents or cleaning agents
    Consult Unison Manual L-1363 for proper cleaning procedures. Correct as necessary.

Schwerer Start
1. Worn or fouled spark plugs. Arcing ignition lead.
Inspect and replace as necessary

2. Mag Impulse Coupling not operating properly.
Remove and check for binding, worn or broken impulse coupling parts.

3. Impulse Coupling is magnetized.
Remove and demagnetize or replace impulse coupling.

4. Low voltage at vibrator input.
Measure voltage between vibrator terminal marked “in” and the ground terminal while operating starter. Must be at least 8 volts on 12 volt systems, or 13 volts on 24 volt systems.

5. Inoperative vibrator.
If voltage is adequate, listen for buzzing of vibrator during starting.If no buzzing is heard, either the vibrator is inoperative or the circuit from the “Output” terminal on the vibrator to the switch and magneto points is open. Check both “Switch” and “Retard” circuits. Also check for good electrical continuity through switch and through magneto points.

6. Retard contact assembly in retard (dual contact) magneto not operating electrically
Engine may kick back during cranking due to advance timing of ignition.
Retard points may not be closing due to improper adjustment, or may not be electrically connected in the circuit due to a poor connection. Inspect retard points to see if they close. Check for proper contact at the “SWITCH” and “RETARD” terminals of retard (dual contact assembly) magneto and at the vibrator. Check wiring.

7. Vibrator-magneto combination not “putting out” electrically.
Turn engine in proper direction of rotation until retard points just open on No. 1 cylinder position. Remove input connection from starter to prevent engine turning, and while holding No. 1 plug lead 3/16 inch from ground, energize vibrator by turning switch to start. Plug lead should throw a 3/16 inch spark. If spark is weak or missing, install new vibrator. If this does not correct trouble, remove magneto and check for improper internal timing or improperly timed distributor gears.

8. Magneto improperly timed to enginge.
Check magneto-to-engine in accordance with Engine Manufacturer’s instructions.

9. Advance contact assembly out of adjustment (internal timing off).
Check magneto timing per paragraph 6.2.3. step G. (4) of PERIOD MAINTENANCE.

10. Retard points opening too late.
Check timing of retard points according to paragraph 6.2.3. step G. (4) (e) of PERIODIC MAINTENANCE.

Triebwerk läuft rau
1. Worn or fouled spark plugs. Worn ignition leads.
Install new spark plugs. Check plug leads for continuity and breakdown.

2. Worn or fouled magneto contact assemblies.
Check magneto contact assemblies for burning or dirt. (Main and Retard.) See PERIODIC MAINTENANCE, paragraph 6.2.1 steps A., B., and C.

3. Carbon tracked distributor block (79).
Replace distributor block (79).

Magneto Drop-off Check Out of Limits
1. Magneto out of time.
Check magneto-to-engine timing in accordance with Engine Manufacturer’s instructions.

2. Contact assemblies not opening properly.
Inspect contact assemblies for proper opening. See PERIODIC MAINTENANCE, paragraph 6.2.3. step G.

3. Faulty plugs or leads
Check plugs and leads

4. No drop-off noted – open capacitor
Check capacitor as specified in GENERAL OVERHAUL, paragraph 7.2.5.

5. Carbon-tracked distributor Block (79)
Replace distributor block (79)

Schwerer Start
1. Worn or fouled spark plugs. Arcing ignition wire.
Inspect and replace or repair as necessary.

2. Mag Impluse Coupling not operating properly.
Remove and check for binding, worn or broken impulse coupling parts.

3. Impulse Coupling is magnetized.
Remove and demagnetize or replace impulse coupling.

4. Low voltage at vibrator input.
Measure voltage between vibrator terminal marked “in” and the ground terminal while operating starter. Must be at least 8 volts on 12 volt systems, or 13 volts on 24 volt systems.

5. Inoperative or defective vibrator
If voltage is adequate, listen for buzzing of vibrator during starting. If no buzzing is heard, either the vibrator is defective or the circuit from the “Output” terminal on the vibrator to the retard (dual contact assembly) magneto is open. Check both “Switch” and “Retard” circuits. Also check for good electrical ground.

6. Retard contact assembly in retard (dual contact) magneto not operating electrically.
Engine may kick back during cranking due to advance timing of ignition. Retard points may not be closing due to improper adjustment, or may not be electrically connected in the circuit due to a poor connection. Inspect retard points to see if they close. Check for proper contact at the “Switch” and “Retard” terminals of retard (dual contact assembly) magneto and at the vibrator. Check wiring.

7. Vibrator-magneto combination not “putting out” electrically.
Turn engine in proper direction of rotation until retard points just open on No. 1 cylinder position. Remove input connection from starter to prevent engine turning, and while holding No.1 plug lead 3/16 inch from ground, energize vibrator by turning switch to start. Plug lead should throw a 3/16 inch spark. If spark is weak or missing, try new vibrator. If this does not correct trouble, remove magneto and check for improper internal timing or improperly meshed distributor gears.

8. Magneto improperly timed to engine.
Check magneto-to-engine timing in accordance with Engine Manufacturer’s instructions.

9. Advance contact assembly out of adjustment (internal timing off).
Check magneto timing per paragraph 9.2.10 of Assembly.

10. Retard contacts opening too late.
Check timing of retard contacts according to paragraph 9.2.10 of Assembly.

Triebwerk läuft rau
1. Faulty spark plugs. Faulty ignition leads.
Try new spark plugs. Check plug leads for continuity and breakdown.

2. Faulty magneto contact assemblies
Check magneto contact assemblies for burning or dirt. (Main and Retard) See Periodic Maintenance, paragraph 6.2.1 steps A, B, and C.

3. Carbon-tracked distributor block (21)
Replace distributor block (21)

Magneto Drop-off Check Out of Limits
1. Magneto out of time.
Check magneto-to-engine timing in accordance with Engine Manufacturer’s instructions.

2. Contact assemblies not opening properly.
Inspect contact assemblies for proper opening. See Assembly, paragraph 9.2.10.

3. Faulty plugs or leads. No drop-off noted -- open capacitor.
Check plugs and leads. Check capacitor as specified in General Overhaul, paragraph 7.2.5.

4. Carbon- tracked distributor block (21)
Replace distributor block (21)

Schwerer Start
1. Worn or fouled spark plugs
Arcing ignition lead
Inspect and replace or repair as necessary.

2. Impulse Coupling not operating properly
Remove and check for binding, worn or broken impulse coupling parts. Ensure D6LN-2031 Types incorporate latest “Heavy Spring” Impulse Coupling Assembly.

3. Impulse Coupling is magnetized.
Remove and demagnetize or replace impulse coupling. Inspect engine for magnetized components and demagnetize all such components.

4. Low voltage at vibrator input
Measure voltage between vibrator terminal marked “in” and the ground terminal while operating starter. Must be at least 8 volts on 12 volt systems, or 13 volts on 24 volt systems.

5. Inoperative vibrator
If voltage is adequate, listen for buzzing of vibrator during starting. If no buzzing is heard, either the vibrator is inoperative or the circuit from the “BO” terminal on the vibrator to the switch and magneto points is open. Check for good electrical continuity from the BO terminal, through switch and through both main and retard magneto points.

6. Retard contact assembly in retard (dual contact) magneto not operating electrically. Engine may kick back during cranking due to advance timing of ignition.
Retard points may not be closing due to improper adjustment, or may not be electrically connected in the circuit due to a poor connection. Inspect retard points to see if they close. Check for proper contact at the “SWITCH” and “RETARD” terminals and at the vibrator. Check wiring.

7. Vibrator-magneto combination not “putting out” electrically.
Turn engine in proper direction of rotation until retard points just open on No. 1 cylinder. Remove input connection from starter to prevent engine turning, and while holding. No. 1 plug lead 3/16 inch from ground, energize vibrator by turning switch to START. Plug lead should throw a 3/16 inch spark. If spark is weak or missing, install new vibrator. If this does not correct trouble, remove magneto and check for improper internal timing or improperly timed distributor gears.

8. Magneto improperly timed to engine.
Check magneto-to-engine in accordance with Engine Manufacturer’s instructions. Inspect contact assemblies per PERIODIC MAINTENANCE, paragraph 6.2.1. Adjust and replace parts as necessary.

9. Main contact assembly out of adjustment (internal timing off)
Check magneto timing per paragraph 9.2.8 of ASSEMBLY.

10. Retard points opening too late.
Check timing of retard points according to paragraph 9.2.8 step K of ASSEMBLY.

Triebwerk läuft rau
1. Worn or fouled spark plugs
Install new spark plugs

2. Worn ignition leads
Check plug leads for continuity and breakdown.

3. Worn or fouled magneto contact assemblies
Check magneto contact assemblies for burning, melting, or contamination. See PERIODIC MAINTENANCE, paragraph 6.2.1 step A., B., and C.

4. Magneto improperly timed to engine
Check magneto-to-engine in accordance with Engine Manufacturer’s instructions. Inspect contact assemblies per PERIODIC MAINTENANCE, paragraph 6.2.1. Adjust and replace parts as necessary.

5. Carbon tracked distributor block (1-27)
Replace distributor block (1-27)

Magneto Drop-off Check Out of Limits
1. Magneto improperly timed to engine.
Check magneto-to-engine in accordance with Engine Manufacturer’s instructions. Inspect contact assemblies per PERIODIC MAINTENANCE, paragraph 6.2.1. Adjust and replace parts as necessary.

2. Main contact assembly out of adjustment (internal timing off).
Check magneto timing per paragraph 9.2.8 of ASSEMBLY.

3. Worn plugs or leads.
Check plugs and leads.

4. No drop-off noted -- open switch connection.
Check capacitor as specified in GENERAL OVERHAUL, paragraph 7.2.5. Verify continuity of switch lead.

5. Carbon-tracked distributor block (1-27)
Replace distributor block (1-27)

Störungen im Funk
1. Malfunctioning spark plugs
Replace spark plugs.

2. Frayed shielding at spark plug terminal, magneto cover, or intermediate point on harness lead.
Remove and replace lead.

3. Inadequate shielding ground at spark plug terminal or magneto cover
Remove and replace inner ferrule (2-7, 2-7a) following procedures in ASSEMBLY paragraph 9.3