1988 Johnson Evinrude "CC" 9.9 thru 30 Service Manual, P/N 507660, Page 56Get this manual
Warning Horn Test
INote To avoidinpossible power head damage, be sure to check the the warning horn is operating conditionIt is advisable
horn at the start of each boating season and periodically during the seasonAt Remote Control check of the warning horn can be made by turning the key switch to the ON position and inserting another key or thin piece of metal into the slot in the controlThe horn should sound If the horn does not sound, check the horn and the complete systemAt the Engine 1Disconnect bullet connector at temperature switch2Connect engine harness half of bullet connector to clean engine ground3With the ignition switch in the ON position, the horn should soundIf the horn does not sound but other electrical components function correctly, the horn or wiring may be damagedRepair or replace as required Refer to Section Powerhead to test temperature switch