Piper PA-44-180 SEMINOLE Maintenance Manual page 685

After the first 50 hour period and every 100 hours thereafter, the magneto ignition system should be checked.
If engine operating troubles develop which appear to be caused by the ignition system, it is advisable to check the
spark plugs and wiring first before working on the magneto. Should trouble appear definitely associated with the
magneto, the most effective measure is to install a replacement magneto which is known to be in satisfactory
condition and send the suspected unit to the overhaul shop for test and repair. Should this not be possible, a
visual inspection of the following items may disclose the source of trouble.
1. Check the lead terminals for definite contact with spring contacts in outlets.
2. Remove the harness outlet cover from the magneto and inspect for the presence of moisture and carbon
tracking due to moisture.
3. Check contact springs in distributor block for evidence of spark erosion.
4. Check height of contact springs (0.422 maximum from top of block tower to spring). (Refer to Figure 74-
1.)
5. With the cover and harness separated from the magneto housing, check contact assemblies to see that cam
follower is securely riveted to its spring.
6. Examine the contact points for excessive wear or burning. Figure 74-2 shows how the average contact point
will look when surfaces are separated for inspection.
DO NOT OPEN POINT CONTACTS MORE THAN .0625 OF AN INCH FOR
E X A M I N ATION OF CONTACT SURFACES EXCESSIVE SPREADING OF
THE BREAKER POINTS WILL OVERSTRESS AND DAMAGE THE
CONTACT SPRING.
Desired contact surfaces have a dull gray, sand-blasted (almost rough) or frosted appearance, over the area
where electrical contact is made. This means that points are worn in and mated to each other, thereby providing
the best possible electrical contact and highest efficiency of performance. Minor irregularities or roughness of
point surfaces are not harmful. (Refer to Figure 74-2, center.) Neither are small pits or mounds, if not too
pronounced. If there is a possibility of pit becoming deep enough to penetrate pad (refer to Figure 74-2. right),
reject contact assembly.
No attempt should be made to stone or dress contact points. Should contact assembly
have bad points or show excessive wear, the complete contact assembly should be
replaced.
7. Check condition of cam follower felts for proper lubrication. If oil has migrated from one follower felt to
another, it may be necessary to remove the lubrication from one felt strip while oiling another. If felt is
overlubricated, remove oil by using a clean, lintless cloth. If dry, apply one or two drops of Bendix Breaker
Felt Lubricant 10-86527.
PIPER AIRCRAFT
PA - 4 4 - 1 8 0 / 1 8 0 T
AIRPLANE MAINTENANCE MANUAL
— CAUTION —
— Note —
3F20
7 4 - 11 - 0 1
Page 74-03
Revised: May 15, 1989