warning horn on constantly

[lromme]

yesterday morning as soon as I tuned the key on my 98 merc 115 to on,I got a solid warning horn.this has never happened before,it stayed on all the time.I started the engine normally,the horn stayed on. there is plenty of oil in the tank.I don't have the aux feeder tank only the motor mounted tank that holds about a gallon.I ran the motor the night before without a problem.I am wondering about an oil presure sensor .any other idea's?

 

[jarand82]

Re: warning hornon conctantly

Re: warning hornon conctantly

check the heat sensor

 

[emckelvy]

Re: warning horn on constantly

If there's a problem with the oil tank float or the magnetic reed switch in the bottom of the oil tank, you may get an alarm. Try unplugging the oil tank alarm switch and see what happpens............ed

 

[lromme]

Re: warning horn on constantly

is there a diference in the warning horn? meaning a solid sound for overheating vs. a few short blasts for oil presure?
where will I find the heat sensor?the temp gage was reading like 125 very strange for a cold motor.

 

[joed]

Re: warning horn on constantly

Oil warning is usually a beep beep beep.
Solid beeping is the heat sensor or the oil warning module has failed.
Heat sensor is a tan wire. Oil sensors are blue wires. The oil module is wired in parallel with the heat sensor so either the module or the sensor can set off the beep.

See this post for my experiences with a 60 hp.

http://forums.iboats.com/showthread.php?p=1772127#post1772127

 

[emckelvy]

Re: warning horn on constantly

OK, the other way then, I forgot!

So if you were to disconnect the heat sensor, and the alarm still went off continuously............likely to be the alarm module, eh?

 

[j_martin]

Re: warning horn on constantly

There is a single alarm wire coming from the engine to the control set. If it is grounded, the alarm sounds. The Overheat sender will ground it solid, making it sound solid. The oil alert normally grounds it intermitently, making it go beep, beep, beep.


Find the terminal where the oil alert and temp sender wires come together. Take all the wires off and see if the alarm quits. If it doesn't, the fault is in the wiring harness. If it does, reconnect the wires one at a time till it goes off. There's your fault.

hope it helps
John.

 

[joed]

Re: warning horn on constantly

The wire from the control is tan coloured. You will find it connected via a Y type connection to the module and the sensor. On my 60 it was on the starboard side at the bottom of the head. The module is located behind the ingnition module where the main control wiring enters. Sort of behind the tilt switch.
There is a purple (power), black(ground), tan(beeper) and two blue(oil tank level sensor) wires. Some of the units actually have a oil pump motion sensor, so yours may be slightly different.

 

[HeavyDee63]

Re: warning horn on constantly

Does your motor have a water/fuel seperator filter with a sensor connected to the filter ? There are three things that will set the alarm- oil,heat and water in the filter. If it does disconnect the wire to the sensor and remove the filter ,pour the liquid in the filter into a clear container and pour some gas into it,the water will sink to the bottom if it has any in it. You can reuse the filter if the sensor and filter is not damaged.