Next on the list....

[Diverted Income]

Figure out why port engine has no warning horn on flybridge or lower station, and why starboard doesn't have a functioning volt meter at either station. More boat mysteries to solve!

[Commissionpoint]

Grounds. (My guess anyways)

My lower port alarm went out just before I hauled last fall. I didn't mess with it. Figured I'd look into it when spring came around.

Got a good multi-meter?

[Big D]

.....Got a good multi-meter?

And do you know how to use it and where?

Could be grounds as Michael suggested re the meters. And for the alarms, could also be the switch at the engine, wiring harness/plug, and the horns themselves.

[Commissionpoint]

Ok. Lets see if I can DIY multi-quote.

.....Got a good multi-meter?

And do you know how to use it and where?

Right. I guess I assume too often.

Could be grounds as Michael suggested re the meters. And for the alarms, could also be the switch at the engine, wiring harness/plug, and the horns themselves.

Also, depending if he has the pre or post facelift F-32 lower station; the indicator light (or not) for the engine alarm is on that circuit too. I think that went away after '77.

[Diverted Income]

.....Got a good multi-meter?

And do you know how to use it and where?

Could be grounds as Michael suggested re the meters. And for the alarms, could also be the switch at the engine, wiring harness/plug, and the horns themselves.

Yup - know how to use a meter. Been doing electrical control work and automation for 20+ years now.

[Big D]

....Yup - know how to use a meter. Been doing electrical control work and automation for 20+ years now.

That's half the battle

[LandVF36]

I've replaced 3 or 4 alarms on my F36. Its a series circuit with the oil pressure sender. If the key is on, there is +12 v to the bulb in the dash, then the horn and on to the oil pressure sender. When there is no oil pressure, the sender provides the ground and the light will be on and buzzer will sound. As soon as you have minimal oil pressure, the output of the sender no longer provides a ground and the buzzer stops / light goes off.

So, if you still have a functioning idiot light, the buzzer has just died. I found Cuttler-Hammer buzzers that were the exact same type online.

[Big D]

I've replaced 3 or 4 alarms on my F36. Its a series circuit with the oil pressure sender. If the key is on, there is +12 v to the bulb in the dash, then the horn and on to the oil pressure sender. When there is no oil pressure, the sender provides the ground and the light will be on and buzzer will sound. As soon as you have minimal oil pressure, the output of the sender no longer provides a ground and the buzzer stops / light goes off.

So, if you still have a functioning idiot light, the buzzer has just died. I found Cuttler-Hammer buzzers that were the exact same type online.

I suspect you mean a parallel circuit. In a series circuit, if one of the loads fails or opens electrically, none of the other loads in the circuit will work, ie; blown lamp will take out the buzzer (old string of x-mas lights). From a practical point of view, a parallel circuit provides a redundancy of the warning function as well as providing full voltage to all loads rather than deviding the source voltage between loads. I also suspect you are reffering to the oil pressure switch rather than sender as that is it's function. The sender is usually reffered to as the variable resistive device that sends a signal to a gage. A play on words but wanted to throw that in so we are directing the testing to the correct piece of hardware as both exist on the engine. But yes, it's a good observation; if one of the warning devices is working, it's an indication that the switch is functional.

[LandVF36]

I stand corrected. Its IS and oil pressure switch (n.c.) on the block of each engine that controls the lights and buzzer, not a "sender". The pressure switch opens when oil pressure is present.
On my 73 F36, the circuit was a series circuit. The logic of it being a series circuit made no sense to me either. Buzzer is open, you get no light. If the light is open (burnt out) you get no buzzer. Really a bad design as either of these can fail and then IF you every really do loose oil pressure, you would get no warning until all of the magic smoke leaves your power-plant

[Diverted Income]

Actually it is a series circuit. Oil pressure switch (N.O.), Trans temp and water temp also must open on high temp. If the control side loses the ground, alarm sounds. I have neither horn nor lights at either station for Port engine. Makes me wonder if the oil pressure switch got jumped out. Will dig into it next time.
http://www.u-oil.net/Documents/MIE230%20-%20Copy.pdf

[Big D]

.....On my 73 F36, the circuit was a series circuit....Really a bad design as either of these can fail and then IF you every really do loose oil pressure, you would get no warning until all of the magic smoke leaves your power-plant

I would change that and put it up there as a priority fix. It should be really easy to do because it's simply a matter of switching up the leads at the buzzer and lamp so that the line from the switch feeds both lamp and buzzer rather than passing through one to the other. In other words, one end of the lamp and buzzer both hook up to the lead from the switch. This makes it a parallel circuit providing source voltage to both loads regardless if one of the loads has failed.

It should be kept in mind that the alarm circuit is only as good as the operator at the helm. Even if both warning lamp and buzzer function properly, a failed switch will render the warning system useless. If the switch fails in the open position, no alarm will sound. For this reason, it is incumbent on the operator to listen for the horn and look for a lit lamp when turning the ignition key before the engine builds up oil pressure. This will put you on notice that the system is or is not working. It acts as a diagnostic of the warning devices if you will. Ignoring this "start-up" warning may cost you big $$. A while back, Mercury came out with a start-up delayed horn device to eliminate the nuisance warning. I never did like those as you have no idea of knowing whether the warning system and its components are working or not unless you left the key in the ON position for a while prior to starting the engine...something nobody does. Of course now on the newer engines, the first thing you hear is a beep, part of which tells you that the horn works.

[Big D]

Wrong quote...read on

[Big D]

Ooops, wrong quote. Here we go:

Actually it is a series circuit. Oil pressure switch (N.O.), Trans temp and water temp also must open on high temp. If the control side loses the ground, alarm sounds. I have neither horn nor lights at either station for Port engine. Makes me wonder if the oil pressure switch got jumped out. Will dig into it next time.
http://www.u-oil.net/Documents/MIE230%20-%20Copy.pdf

I was reffering to the way the loads; lamp and buzzer hook up to the switch per the description;

...there is +12 v to the bulb in the dash, then the horn and on to the oil pressure sender....

Maybe they currently are in parallel and I'm just getting hooked up on the way LV described the circuit, guess it could be interpreted both ways. But yes, no question from the load to the switch it would have to be in series. But both loads must be in parallel.

[Diverted Income]

That does seem goofy to put the lamp and the horn in series. Maybe that is all it is, toasted lamps at both stations. Ahhh I wish I was closer to the boat!

[Commissionpoint]

That does seem goofy to put the lamp and the horn in series. Maybe that is all it is, toasted lamps at both stations. Ahhh I wish I was closer to the boat!

I don't think you have lamps in 1982, just the buzzers.