74-10-00 Page 74-17 Revised: February 28, 2002
PAGES 3H22 THRU 3H24 INTENTIONALLY BLANK

74-10-00 Page 74-18 Issued: April 1, 1997
3H22
DISTRIBUTION IGNITION HARNESS INSPECTION OF HARNESS
1.  
Check lead assemblies for nicks, cuts, mutilated braiding, badly worn section or any other evidence of physical damage. Inspect spark plug sleeves for chafing or tears, and damage or stripped threads on coupling nuts. Check compression spring is not broken or distorted. Inspect grommet for tears. Check all mounting brackets and clamps to see that they are secure and not cracked.

2.  
Use an ohmmeter, buzzer, or other suitable low voltage device, and check each lead for continuity. If continuity does not exist, wire is broken and must be replaced.

3.  
For electrical test of harness assembly, use high voltage, direct current tester such as TAKK model 86 or 86A or equivalent direct current high voltage tester capable of delivering test potential of 10,000 volts. Connect ground lead to high voltage tester to outer shielding braid of a single lead. Connect plug terminal. Turn tester ON and apply 10,000 volts. Insulation resistance should be 100 megohms minimum. Check all other harness leads in same manner.

4.  
Minor repair to harness assembly, such as replacement of contact springs, spring retainer assemblies, insulating sleeves, or of one lead assembly, is done with harness assembly mounted on engine. To replace more than one lead assembly or cable outlet plate, harness should be removed from engine and sent to an overhaul shop.

REMOVAL OF HARNESS
1.  
Disconnect clamps holding wires to engine and accessories.

2.  
Loosen coupling nuts at spark plugs and remove insulators from spark plug barrel well. Do not  damage insulator spring when withdrawing insulator.

3.  
Place a guard over harness insulators.

4.  
Remove harness assembly terminal plate from magneto.

5.  
Remove harness from airplane.

DISASSEMBLY OF HARNESS
1.  
To remove spring, Slick M-2929, from damaged lead, turn spring counterclockwise while pulling gently. This will remove spring and M-1498 electrode screw from end of coiled conductor.

2.  
To separate spring and screw, hold electrode screw with pliers and turn spring clockwise until it is through the threaded portion.

3.  
Remove insulator sleeve from end of wire.

4.  
To remove lead from M-1569 harness cap, use diagonals or cutting pliers and cut lead off close to cap. Use drift or punch to tap ferrule loose from harness cap.

— Note —
Further service on Slick harnesses will require the use of Slick T-200 or M-1495 Service Tool Kit, obtained from:
Unison Industries.
530 Blackhawk Park Avenue
Rockford, IL 61161

74-20-00 Page 74-19 Issued: April 1, 1997

74-20-00 Page 74-20 Issued: April 1, 1997
3I2

74-20-00 Page 74-21 Issued: April 1, 1997
HARNESS ASSEMBLY INSTRUCTIONS
1.
Cut a piece of harness wire to length required. Do not stretch wire when measuring it.

2.
On magneto end, make a final mark one inch from wire end. Another mark must be made 0.9375 inch from spark plug end of wire.

3.
Flare out shielding, then without allowing any shielding to fold under, insert Slick T-112 or M-1743 stripping tool under braided shielding. (Refer to Figure 74-10.)

4.  
Make sure stripping tool is inserted past cutting mark, and cut shielding with a sharp knife using a rolling motion. Remove shielding and stripping tool. Do not cut silicone insulation. (Refer to Figure 74-11.)

5.
Cut exposed insulation 0.125 inch back from end and roll insulation clockwise to remove. Do not use a pulling motion when removing insulation. Trim end of coiled conductor to make a clear hole for inserting stud. (Refer to Figure 74-12.)

6.
Using T-111 or M-1742 pin vise, insert T-110 or M-1741 drill (#72 drill), drill out silicone rubber from inside coiled conductor approximately 0.5 inch deep. (Refer to Figure 74-13.)

7.
On spark plug end of wire install M-1673 nut followed by M-1671 female taper hex ferrule. (Refer to Figure 74-14.)

8.
After installation of nut and ferrule, bend and rotate silicone insulation as per figure 74-15 to flare out shielding so drive ferrule can be inserted. Do not cut silicone insulation with sharp braiding while wire is being rotated.

— CAUTION —
DO NOT REUSE THE M-1458 DRIVE FERRULE.

9.
On spark plug end of wire install M-1458 male tapered drive ferrule over silicone insulation and under shielding to within 0.0625 inch from flange of ferrule. Make sure that shielding is away from ferrule flange then slide ferrule M-1671 over the M-1458 drive ferrule until tight. (Refer to Figure 74-16.)
　
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