Mercury 305 CID - Thunderbolt IV Ignition Module; Distributor Repair; Removal

THUNDERBOLT IV AND V IGNITION SYSTEM - 4B-990-823225--1 1096
Thunderbolt IV Ignition Module
IGNITION MODULE MOUNTED ON EXHAUST
ELBOW
1. Unplug wiring harness connector from ignition
module.
2. Remove fasteners and hardware retaining igni-
tion module to exhaust elbow. Remove module.
NOTE: Do not disturb spacers between ignition mod-
ule plate and exhaust elbow, unless replacing
spacers.
IMPORTANT: BLACK ground (–) wire from engine
harness must be placed under ignition module
fastener when mounting module.
3. Replace ignition module using existing hard-
ware. Tighten fasteners securely. Be certain
BLACK ground (–) wire is in position.
4. Check that terminals of wiring harness connector
are clean and free of corrosion. Plug connector
into ignition module.
IGNITION MODULE MOUNTED ON
DISTRIBUTOR
1. Unplug wiring harness connector from ignition
module.
2. Remove stainless steel screws retaining ignition
module to distributor body. Remove module.
IMPORTANT: Thermalconductive Grease must
be applied to the back of the ignition module to
conduct heat away from the module and to pre-
vent corrosion.
3. Apply a thin coat of Thermalconductive Grease
evenly across the metal back of the ignition mod-
ule.
4. Install ignition module using the stainless steel
screws. Torque screws to 10 lb. in. (1.1 N·m).
5. Check that terminals of wiring harness connector
are clean and free of corrosion. Plug connector
into ignition module.
Distributor Repair
Removal
1. Unplug wiring harness from ignition module on
distributor housing, or disconnect wires from igni-
tion module mounted on exhaust elbow. Discon-
nect sensor wires.
2. Remove distributor cap. Do not remove high ten-
sion leads unless necessary.
3. Crank engine over until timing marks line up and
rotor is pointing toward No. 1 cylinder on distribu-
tor cap.
4. Mark distributor housing in reference to engine
block.
5. Remove bolt and hold-down clamp and remove
distributor.
IMPORTANT: To simplify distributor installation,
do not turn crankshaft when distributor is re-
moved from engine.