I have no audible alarm when turning my key on 1999 4.3 mercruiser

[toolman4]

I am about ready to test my boat but I have no audible when I turned the key on. I want to make sure it is functioning correctly. This is on a 1999 starcraft bowrider. I don't know if I had an audible before I swapped motors either because I only had it out twice. What wires should I be looking for on the harness and what sound should it make on key turn?

 

[jkust]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

If it is like my carbed 4.3 liter, 2003 Mercruiser, you would hear an ear piercing, high pitched sound that is impossible to ignore. 2002 and newer MPI Mercruisers have a different set of beeps and I'm unsure of what EFI, post 2005 Mercruisers make.

 

[Don S]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

You should have a horn of some kind, how it sounds and what the problem is depends on if you have a carbed engine or EFI.

 

[toolman4]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

Its the carbed model with the thunderbolt 4 ignition. I don't have any noises. The tan/blue wires are all plugged in where they are supposed to be and I checked the fuses by the battery. The motor idles good and everything is working like it is suppposed except for that alarm. The schematic doesn't show where the alarm is located. Also how do I test it when I find it. There is a black spade on top of the motor that isn't connected to anything coming out of the harness that plugs into drive unit oil level, water temp, ignition base timing and such. Is that supposed to go somewhere?

 

[Don S]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

When you turn the key on, the alarm should come on because you have no oil pressure. The alarm should continue until you have around 6 psi of oil pressure built up.
To test the alarm, turn the key on, and take one of the tan/blue wires off one of the switches and ground it to a clean ground. The alarm should sound.

 

[Bondo]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

except for that alarm. The schematic doesn't show where the alarm is located.

Ayuh,.... It oughta be under the dash, if it's got 1....

 

[Don S]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

Ayuh,.... It oughta be under the dash, if it's got 1....

In the 90's, he's got one.

 

[Bondo]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

In the 90's, he's got one.

Ayuh,.... at 13 years old, 'n untold POs,... it may Not....

 

[toolman4]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

Thanks for the replies. I'll try grounding it tomorrow. I looked under my dash and there is a horn but I don't really see anything else that looks like an alarm. The horn is on the far side so I couldnt tell how many wires were going to it. I'll try to get a better look tomorrow. The tan blue lines on the schematic say that I have an alarm if I have those wires right? How do I tell if I have the thunderbolt 4 or 5 ignition? I took a pic of that black spade wire if somebody knows if its supposed to go somewhere. Lastly does the wire harness sit on top of block like I have it and are there hot spots you have to worry about?

 

[Don S]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

It's a 98 or 99 model, so it's a Thunderbolt V.
The alarms were put on all those models. Of course if you don't know what it looks like, it's probably going to be hard to spot under the dash board amongst all that wiring. It's only the diameter of a quarter.

Basically, ground a tan/blue wire with the key on and if you hear it. Follow the sound. If you don't hear it, there is a problem, it's either it's missing, broken, or disconnected.

 

[86 century]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

Ok the two I/O gods don't agree the world may end soon.

 

[toolman4]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

I grounded the wire tonite and nothing happened. Crawled as far as i could into the wire hatch and found an sp 571 audible by bell south inc. black in color 5 to 15 volts. It was plugged in, but there was no volts going to it with the key on. I did an ohm check between the tan blue wire (same color as audible wires in back) and the purple wire coming out of the audible and it registered no ohms. Should I be getting ohms between those two wires?

 

[Don S]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

If you don't have voltage on the purple wire, it won't work. The switch on the engine is the ground.
Put a jumper wire with 12V on the purple wire of the buzzer and another jumper on the tan/Blk wire and see if goes beep. If not, go to radio shack and find a new one for 5 bux. If it does go beep and scares the begeebies out of you, fix power to it, and hook the wire up to the switch on the engine.
To test, turn the key on it should sound and stay on till you start it and get oil pressure.

 

[toolman4]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

Thanks Don. I like the begeebies scared out of me every once in a while So just to clarify the other tan/blue wire gets a jumper to ground right?

 

[Don S]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

You could hook it up a ground to test the buzzer only. If it works then, hook the tan/blue wire up at both end to make sure it still comes on.
It should sound all the time unless you have oil pressure (aka engine running).

 

[toolman4]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

There was power to the horn so I need a horn. Don do you mean the pc pizzeo alarms? I think they are like 90 decibals or something. Otherwise the mercruiser alarm is $25.

 

[Don S]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

Radio Shack has all kinds, ask them.

 

[toolman4]

Re: I have no audible alarm when turning my key on 1999 4.3 mercruiser

I just thought I would report back. Got the pizzeo alarm at radio shack for 7 bucks and chose the 85 decibal one which was just about right. Hooked her up and she buzzed until I had oil pressure. Grounded one of the alarm components in back and it buzzed again so she's working great. Thanks for everybody's help!