Warning Horn Signals

Adapted to Hypertext by James W. Hebert

Adapted from the owner's manual provided with a 1992 Evinrude 225-HP motor, the warning horn signals from older Johnson and Evinrude outboard motors are described and interpreted. The warning horn cadences are typical of OMC motors made prior to 1996. In 1996 OMC changed to a System Check gauge which visually identifies the nature of the alarm, and the warning horn no longer gave distinctive signals.

IMPORTANT—A warning horn is built into OMC prewired remote controls or is part of the OMC accessory wiring harness. The warning horn has the following distinct signals that will alert you to engine problems.

When the ignition key is turned to the ON position, the warning horn will beep once, indicating the horn is working.

Horn sounds continuously and engine WILL NOT exceed 2,500-RPM Engine overheat Reduce engine to IDLE speed and return shift handle to NEUTRAL position NOTE #1
Horn sounds rapid, short tones that vary with engine speed No oil flow from pump STOP engine or limit engine speed to a
maxumum of 1,500-RPM
Horn sounds one short tone every 20 seconds Low oil level in oil tank Refill oil tank NOTE #3
Horn sounds continuously at or near full throttle, but engine speed is not affected Fuel restriction Reduce engine to IDLE speed NOTE #4


If the engine overheats, the S.L.O.W.™ overheat warning system will automatically limit engine speed to approximately 2,500-RPM. The overheat problem must be corrected and the warning system reset before you can return to normal operation.

For information about evaluating the overheat problem and possible "on-the-water" fixes, refer to Operation Section, ENGINE OVERHEATING.

After the engine has cooled and the warning horn stops, shut off the engine to reset the overheat warning system. Restart the engine for normal operation.

NOTE: If the engine overheats repeatedly, see your DEALER. After an engine overheat, have your DEALER torque the engine's cylinder head screws, and, if equipped, exhaust cover screws.


DO NOT operate the engine above 1,500-RPM if the oil pump is not working. See your DEALER for service.

NOTE: When the warning horn signal indicates no oil from the pump, operating above 1,500-RPM can result in serious engine damage. If you must operate the engine above 1,500-RPM to return to harbor, oil must be mixed with the gasoline at a 50:1 (2% oil) fuel/oil ratio. Refer to Fuel and Oil Section, FUEL MIXING.


Oil is at reserve level in oil tank (approximately 1/4-full). Avoid operating the engine on oil reserve. Refill oil tank with recommened oil as soon as possible. Refer to Fuel and Oil Section, FILLING OIL TANK.

NOTE: Failure to refill the tank could result in serious engine damage. If oil tank is run dry, the oil hose must be purged of air. Refer to Fuel and Oil Section, OIL HOSE INSTALLATION.


If the warning horn signal stops as engine RPM is reduced, a fuel restriction is indicated. The engine can be operated at a reduced throttle setting to return to harbor.

Inspect fuel filter element for contamination and clean as necessary. Refer to Maintenance Section, FUEL LINE FILTER. Continued warning signals could indicate a problem with the boat's fuel supply system. See your DEALER for service.

If the warning horn does not stop when engine RPM is reduced, an engine overheat is indicated. Refer to NOTE #1.

Differences Between Printed and On-Line Text

This on-line version differs from the printed version only in minor changes in spelling and style. Other sections of the owner's manual to which reference is made unfortunately are not available on-line as hypertext.

DISCLAIMER: This information is believed to be accurate but there is no guarantee. We do our best!

Copyright © 2007 by James W. Hebert. Unauthorized reproduction prohibited! Copying and use of this text and graphic images in any form is prohibited without prior permission. Do not cut and paste this text or these images into other on-line documents.

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Author: James W. Hebert
This article first appeared May 2007.