1993 115CETO warning buzzer problem

[davehank]

The warning buzzer is going off on my 1993 115CETO, and sometimes the rev limiter kicks in. The engine temperature is fine and the main oil tank is full. I'm pretty sure I have a short circuit or ground somewhere but I can't figure out how to track it down.
The warning buzzer goes off when I'm in gear normally around 1800rpm, switches off as soon as I go into neutral. Doesn't go off every time, it's intermittent.
I tried disconnecting each of the temp sensors and the oil tank connector and low oil warning wire, but none of them made any difference.
The 20A fuse under the cowling blew a couple weeks ago and that's when the problem started. It seems the trim-tilt circuit is involved since sometimes the buzzer goes off exactly the same time I hit the trim switch on the remote, and yesterday the tilt-trim stopped working completely for about 5min.
The wires in the engine all look in fairly good condition so I suspect the forward control. Could it be a short in the forward control? Could it be a short in the wires from the remote to the tach, since those wires look a bit shabby?
Thanks

[boscoe99]

Shorts usually either blow fuses, trip circuit breakers or let smoke out of wires. Don't think this is your problem.

If voltage is low to the CDI the warning horn may sound. If you use the trim motor there may be a voltage drop issue if the wiring or the voltage supply (battery) is deficient. Use of the trim motor may be dropping the voltage to the CDI which then causes the horn to sound.

I would start by carefully inspecting every connector on the motor. From the battery cables to all connectors on the motor itself. Maybe connect a voltmeter to the voltage supply line to the CDI to monitor the voltage when the trim is being used. Don't forget the condition of the battery itself. And the battery cables as well.

[davehank]

Thanks

Thanks boscoe99 for pointing me in the right direction. Seems like it was a power supply problem, the 20A fuse in the engine wasn't making a good connection, seems like the fuse was too small for the holder. I changed out both fuse holders for blade type, went for a run today and seems like it's all OK. Thanks for your help!

[boscoe99]

Thanks boscoe99 for pointing me in the right direction. Seems like it was a power supply problem, the 20A fuse in the engine wasn't making a good connection, seems like the fuse was too small for the holder. I changed out both fuse holders for blade type, went for a run today and seems like it's all OK. Thanks for your help!

Yamaha even issued a bulletin about this problem many many years ago.

Thanks for the feed back and even more thanks that you found and fixed the problem.