Murphy HD9063 Series Magnetic Pickup Installation see Figure, Gap Adjustment, Wiring

WIRING

CAUTION: PERFORM THE WIRING OPERATION WITH THE POWER SOURCE “OFF”

1.Connect terminal 5 on the HD9063 to engine ground and connect terminal 4 to battery positive (see Figure 3).

2.Connect the magnetic pickup cable conductors to terminals 6 and 7.

3.If cable is shielded, connect shield to engine chassis ground.

4.If desired, connect a normally open test push button switch between terminals 8 and 9.

5.Connect crank disconnect circuit to crank disconnect termi- nals 1 thru 3 as discussed in Crank Disconnect Relay Function, page 2. On HD9063-USOS models connect the overspeed circuits 1 thru 3 as discussed in Overspeed Relay and Underspeed Relay Function, page 2.

6.Connect the overspeed circuits to overspeed terminals 10 thru 12 as discussed in Overspeed Relay and Underspeed Relay Function, page 2.

				(+) ( ) (+) ( )
	1	2	3	4	5	6	7	8	9	10 11 12
	K1									K2
										12
To Engine	Common									Common
Crank Control											To
Circuit	Normally Open									Normally Open
or											Shutdown
to Shutdown	Normally Closed									Normally Closed	Circuits
Circuits
(HD9063-USOS)										Test
										Pushbutton

DC Positive

DC Negative

(Engine Ground)

From Magnetic Pickup

Figure 3

MAGNETIC PICKUP INSTALLATION

A magnetic pickup is an AC generator. It is normally installed into the flywheel housing of an internal combustion engine, so that the starter ring gear acts upon it to generate a voltage pulse each time a gear tooth passes the end of the sensor.

Magnetic Pickup Installation (see Figure 5)

Drill and tap a hole in the flywheel housing (See Specifications Chart below for model and thread size). IMPORTANT: Drilling too deep may damage ring gear teeth. Blow chips with air hose when drilling and tapping hole.

Gap Adjustment

Insert magnetic pickup and turn until it stops at the face of the gear.
Back-off the gear by turning the pickup counterclock-
wise 1/4, 1/2, or 3/4 turn (Figure 4) .
See Gap Chart (above, right) to determine gap	1/4
distance based on the turn. Check gap clear-
ance by rotating the gear completely around.
NOTE: Magnetic pickup gap should be	1/2		3/4
adjusted so that the minimum voltage required
is attained at the engine’s lowest RPM. The
voltage will increase as the speed increases.
		Figure 4
If erratic readings occur, remove magnetic
pickup and check the magnetic tip for metal chips.

Murphy Magnetic Pickup Specifications Chart

Pickup	Total	Threaded	Thread
Model	Length	Length	Size
MP3298*	3 in. (76 mm)	3 in. (76 mm)	5/8-18 UNF
MP7906†	3 in. (76 mm)	3 in. (76 mm)	3/4-16 UNF
MP7905††	4-1/2 in. (114 mm)	4-1/2 in. (114 mm)	3/4-16 UNF

*Replaces 20-01-0080 and MP100. Lead wire hookup (12 in. [305 mm]).

†Replaces 20-01-0081. Lead wire hookup (12 in. [305 mm]). ††Replaces 20-01-0082. Lead wire hookup (12 in. [305 mm]).

Gap Chart

THREAD	1/4	TURN
SIZE		1/2	3/4	1
5/8-18 UNF	.013 in.	.028 in.	.035 in.	.055 in.	G
	(0.33 mm)	(0.71 mm)	(0.88 mm)	(1.39 mm)
3/4-16 UNF	.015 in.	.030 in.	.045 in.	.062 in.	A P
	(0.38 mm)	(0.76 mm)	(1.14 mm)	(1.57 mm)
	Always use a two-conductor shielded cable. Ground the
	shield to a metal frame ground at the engine end only.
Never run these wires
next to spark plug wires
or in wire loom with other
wires carrying inductive
loads or alternating current.
After adjusting,
set locknut.
Drill and tap casing				AC
(see thread sizes in
Specifications).				Meter
	Gap
	(see Gap Chart)		Casing

NOTE: Clean gear casing	Gear (must be made
	of magnetic material).
and magnetic sensor
of metal chips or filings.

Figure 5

HD-96044N page 3 of 4