8-21. MAGNETOS (4000 and 4200 series)
—NOTE—
The 4000 series magnetos are non-serviceable. Refer to the latest revision of
Lycoming Service Letters Nos. L173 and L177.
—CAUTION—
Ascertain that the primary circuit of the engine is grounded before working on the
engine.
8-22. REMOVAL OF MAGNETOS. (4000 and 4200 series) Before removing the magnetos, make sure the
magneto switches are OFF.
a. Remove the harness assembly with the spark plug wire housing from the magneto.
—WARNING—
The magneto is not internally grounded, when the ground lead is disconnected, the
magneto is hot. Removing the harness assembly first and installing them last,
minimizes the danger of starting the engine accidentally when the ground lead is
removed from the magneto.
b. Disconnect the ground lead at the magneto.
c. Remove the nuts and washers, and remove the magnetos from the engine.
8-23. INSPECTION OF MAGNETOS. (4000 and 4200 series) The 4000 series magnetos require very little in
the way of inspection. These units are sealed and should not be tampered with, as this would void their warranty.
(Refer to the latest revision of Lycoming Service Letter No. L 177 and Slick pro rata instruction form No. 1001).
At the time of engine inspection or when a magneto has been removed from the engine. The 4200 series
magnetos can be inspected in the field, the following checks may be performed:
a. The magneto to engine timing for the 4000 series should be checked every 200 hour interval and the
4200 series magneto to engine timing should be checked every 100 hours or at annual inspection, whichever
comes first.
b. Inspect the distributor block for cracks and burned areas.
c. Check the contact assemblies on 4200 series for burning and wear every 500 hours. The following
steps may be performed:
1. Inspect the points for discoloring. If points have a white frosty surface around edges, the
points are functioning properly. Apply M-1827 cam grease sparingly to each cam lobe before reassembly.
2. Inspect points for discoloring and pitting. If these conditions are evident, replace both
condenser and points.
—NOTE—
Point opening for these magnetos is critical. When setting the breaker
points, be sure to stay within the specified .008-.010 inch tolerance. The
most efficient spark is obtained at this point setting.
PIPER AIRCRAFT
PA-28-161 CADET
AIRPLANE MAINTENANCE MANUAL
Issued: FEBRUARY. 28, 1989
POWER PLANT
1J17