instruments switch= alarm

[darkdealer]

After a month of not being out on the water, this past Saturday I attempted to start up my 88 osprey 170 and to my surprise the batteries were near dead. I disconnected the #2 battery and put the leads on a fresh battery to turn the engine over. Once the engine fired up I turned the battery switch from #2 position to #1, well at least that is what I thought. After about 30 seconds of running the motor at high rpms I noticed the fish finder was indicating input voltage too high and cut the motor. When I looked at the battery switch I noticed the switch was turned to off and not #1. I switched it over to #1 and the alarm would sound. I then turned all the instrument switches off and the alarm stopped sounding. I was able to determine that when the "instruments" switch was turned on , the alarm would sound. Does anyone have any idea as to what could be the problem/fix? I checked all the visible fuses and they are intact. After some thought I wonder if having the battery switch on off with the motor running may have caused some damage to the switch or perhaps the instruments switch needs replacement. I am also curious what triggers the alarm to sound? Thanks for your help!

[compcrasher86]

Hmm, you may have done damage to the engine itself. Having the engine running with nothing to charge can do damage to the alternator. However, I do not understand why there is only a problem when "instruments" is switched on. Try taking a voltmeter and check the voltage coming directly out of the engine when it is on and also along various lines.

Check the voltage of the terminal the fishfinder is connected to and see how much that is reading. Post back your results if you can, if not than give us as much information as possible.

It may just be that the fishfinder is misreading the voltage as being too high as the battery died and settings may have been changed/reset.

[darkdealer]

I think the instruments switch may be damaged because it is appears to be powered directly from the battery. Well there is a set of wires that go from the battery terminal to the instruments switch. The alarm sounds when I engage the switch, w/o the engine running. I have not put a charged battery back into the boat yet to fire it up but I am nervous about running the motor with the alarm sounding. It is not the fish finder alarm that is sounding but the boat alarm that I hear when If try to start the boat while patially in gear. It is not just a chirp but a continous loud squeal.

[compcrasher86]

Bypass the switch and temporarily connect the two wires together (the ones the switch would normally control) If you are still getting engine alarm than the problem is not the switch.

Here is a wild guess... The alarm is wired so that it will only go off if the instrument switch is on (which is a poor idea if you ask me) when the switch is on, power is provided and the alarm is going off because of something engine related. Try checking your oil level, see if you are low.

If you are positive the engine is fine, than there must be some kind of short-out or faulty ground. My old warning horn kept going off and I found out that it had disconnected from the dash and was bouncing around hitting grounds and that was making it go off. Because your tone is constant, I would guess that this is not the case but it always helps to trace the wires to and around the warning horn and make sure they are not shorting.

The fact that a simple on-off switch could be causing this blows my mind but you never know. As a last suggestion I would inspect your connections to the various instruments powered from the "instruments" switch and make sure they are secure and not exposed or loose

What model/make/year motor do you have?

*Update: The only way I can imagine the switch being the problem is if the switch was lighted therefore it would need a ground and somehow the switch malfunctioned and is grounding everything. I would inspect other sources

[darkdealer]

Well I did some trouble shooting and veridied all the fuses and wiring is intact on the boat and motor. The instruments switch is fine and all the gauges wereinspected as well. THe bilge is dead and needs to be replaced. But I think the real problem lies with the motor. Perhaps the rectifier was affected and may need to be replaced.

[compcrasher86]

At least you have narrowed down your causes. Out of curiosity, can you trace the wire from the boat alarm and make sure it is not being powered by the instruments switch?

If it is, I highly suggest switching it to an ignition switched source (power is provided when key is switched on), because the boat alarm tells you when somethings wrong with the engine and you always want to know when something is wrong without having to turn on a switch.

Best of luck,

-Matt

[darkdealer]

yes, the alarm is switched to the ignition as well. Out of curiosi, what problems typically trigger the alarm?

[Capt. Bob]

Before doing anything else, make sure you have two fully charged batteries on board. That started the whole problem. Correct that first (if you haven't already) and start from there.

[compcrasher86]

Im not sure what engine you have but if you have an older engine, specifically evinrudes, the alarm system is just a ton of sensors that ground a tan wire whenever something is wrong and that sets off the alarm.

Problems typically include low oil, overheat, over-rev. Some beep if you try to start them in gear and others beep if they sense the engine is not down enough to start. Mine also sometimes beeps when I turn the key, provided the key has been off for at least 2 minutes. I dont know why it does that but it does.

The problem could also be a faulty sensor that is causing the wire to ground. Find out what color the alarm wire is for your specific engine and trace it back through the wiring harness and to the engine. Follow that wire and wherever it is being grounded is the source of the alarm.

I forgot to say, I am assuming you have one of the older motors. If you have a motor with a Systems check feature (typically seen in Evinrudes after '92) then the motor does a check on most of the engine and does a short beep if all is ok. I imagine this system has many many more sensors and a more complex system than just grounding a wire on alarm.