Mallory Ignition Mallory ADJUSTABLE PROPORTIONAL RPM LIMITER 642_643_644 - Manual

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INSTALLATION
INSTRUCTIONS
ADJUSTABLE PROPORTIONAL RPM LIMITER
PART NOS. 642, 643, AND 644
Mallory's Proportional RPM Limiter functions as an engine protection device. As the RPM setting
is reached, the RPM Limiter will cut off the spark. This protects your engine from runaway and
damage.
This limiter can be used in many different applications:
• Marine Use
When a marine engine is under a heavy load and slips out of gear, loses a propeller, breaks a
drive shaft, or the propeller loses contact with the water, engine runaway occurs. The limiter lim-
its RPM and protects the engine.
• Racing
Mallory's RPM Limiter prevents engine damage from missing a shift at high RPM.
• Industrial Use
Runaway engines are common in industrial applications. Mallory's RPM Limiter eliminates
engine damage from over-revving.
INSTALLATION PROCEDURE
1. Install the Proportional RPM Limiter on the inside of the firewall or
a convenient location under the dash. Mount the dial in a visible
location on the dash. Use the metal screws supplied with the limiter.
2. When performing the following operations, cut all leads as short
as possible, leaving enough slack to absorb engine vibration.
Solder and tape all connections.
3. Run the green and black wires through any existing hole in the
firewall. If there is not a convenient hole, drill a 3/16" or larger hole
in the firewall. Be sure to remove all burrs and sharp edges.
4. Connect the green wire to the coil negative (–) terminal.
5. Connect the black wire to a clean ground on the engine block.
6. Connect the red wire to a fused, positive (+) power source, prefer-
ably one that turns on and off with the ignition switch.
NOTES
1. 12 volt negative ground only.
2. Actual limiting RPM may be several hundred RPM less than the
dial indication, depending on the condition of your ignition system
components.
3. Critical limit adjustment should be made using an accurate
tachometer as a reference.
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FORM 41656 (REV. B) 7/98 MADE IN U.S.A. PRINTED IN U.S.A.
550 Mallory Way, Carson City, NV 89701
(775) 882-6600