Noise from outboard motor control box

[blowin]

Hi , my mate has Quicksilver Outboard Motor Remote Control Box fitted . On the return leg of a 5 mile round trip involving plenty of stops for drifts it started to emit a high pitched continuous tone .There was nothing obvious wrong with anything we could see .
Any idea what that means and/or what might have caused it ? ( Instruction book lost a long time ago and I can't find one on the net ) .
I don't know whether it is relevant to add that on first attempts to start up, the battery appeared to be completely dead . It came to life after being moved so presumably that was just a faulty connection . Once started the engine would not run at full power . That sorted itself after a while ( mile or so ) . Coincidence ?
Any thoughts much appreciated .
Cheers

[jonnog]

Sounds to me that the battery was just a coincidence in terms with the control box sound to me like a loss cable or maybe some corroded connector


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[JimC]

What motor is it? Model and Year?

[johnwest]

Check the oil level and pressure in the engine, I think Mercury engines have a low oil sensor/alarm. The lack of full power may be a get-you-home without causing damage due to lack of lubrication.

[blowin]

What motor is it? Model and Year?

It is a Mariner 50 hp 2 stroke . I do know that it is not new but will need to get back to my mate for the year .
The control box is Quicksilver with trim control .
Many thanks for all the replies so far . Much appreciated .

Good luck

[yappo]

Found this hope it helps.

Here is what the manual says for a Mercury 50HP.

Situation One:
Problem: Warning Horn Stays On When Ignition Key is Turned to “ON” Position (Engine Cold).

Faulty Engine overheat sensor. If warning horn sounds a continuous “beep”, the engine
overheat sensor may be faulty. Disconnect tan/blue overheat
sensor lead at bullet connection. Turn ignition key to
“ON” position. If horn stops sounding, the engine overheat
sensor is faulty.

Situation Two:

Problem: Warning Horn Sounds (Continuous Beep) When Engine is Running and Oil Tank is Full.
Disconnect both low oil sensor leads (blue) at bullet connections.
Connect an ohmmeter between sensor leads.
There should be no continuity through sensor. If continuity
exists, sensor is faulty


Yappo

[johnwest]

I see that it's a 2 stroke so no oil pressure in the engine. As far as I know, the warning horn is either intermittent, which indicates an oil injection problem, or continuous which indicates an overheating problem. Can you run the engine ashore in a barrel of water? If so, run it and see if the horn comes on after a while. If it does, check the cooling water stream to see if it is warm or cold, if cold there may be a blockage in the cooling system. Apparently the motor can "pee" well but still not have good circulation through the power head. If the water is warm, you may have a faulty sensor.

[hugo]

The battery aspect might not be a coincidence, you may have a corroded battery post causing a low voltage/current flow problem that can also trigger an alarm on many control units.