99 c115 in rpm reduction mode, no alarm

[RedHead6]

My 115 went straight into rpm reduction mode from a cold start within 5 minutes of idle speed in the marina. Constant misfire at 2000 rpm in neutral and in gear, alarm did not sound. Heads are warm to the touch, water pump is fresh, tell tale strong, runs smooth under 2k rpm and no overheating symptoms. Went back to the dock, turned off and back on, running normal in neutral. Grounded one sensor, went back to reduction mode with the exact same symptoms, no alarm. Hot wired the alarm, it sounded off. Could not reproduce the problem with sensors connected, so I didn't test when disconnected. Bought the outboard new without the oil pump option. All sensor wires look well insulated, but I have not traced the alarm wire to the console and need to figure out why alarm is not sounding in limp. Could a short in the alarm wire cause this? When a CDI goes bad, is this a typical symptom? Your feedback would be appreciated!

[99yam40]

sounds like more that one problem
something is grounding the overheat switch or wire and the buzzer is not functioning
testing of the circuits will be needed
I am not sure how your motor is wired up, but some had 12+ from the ignition switch run to the buzzer and then the ground wire is runs back to the motor and is grounded by the overheat temp switch or the CDI, they maybe tied together somewhere along the way

[RedHead6]

Thanks for the reply 99,
The one clue I had to work with was the alarm not sounding, so I traced the wire harness back to the alarm and found a short. Since I could not replicate the limp mode at the dock, I should have tried to short the harness to see if it would cause a limp mode and disable the alarm. This would verify the fix - it's running fine but needs to be tested on the water.

[99yam40]

what was the wire shorting to?

did you try grounding the temp overheat switch and get the buzzer to sound after the repair?