Need a 12v+ when engine is running

[Punch'Eau]

Hi all, I own a 2000 350 Mariner with 7.4L Mercruiser. It may sound curious but I need to find a place somewhere (preferably at the helm) I will have 12v+, only when an engine is running.
I tought of the hour meters but they receive 12v+ as soon as the ignition key is ON.
Someone has an idea?
I want to install a buzzer that will activate if I loose an engine when trying to dock....

[Viper]

You should already have one for each engine. Take a look behind the helm. Mounted somewhere or tied to the harness should be an alarm horn/beeper/buzzer. If your key is on and the engine isn't running (no oil pressure), the alarm should be sounding. Same happens when you go to start the engine; turn the key to on and wait (delay circuit), the alarm should sound. If it isn't there's an issue somewhere; wiring, beeper/buzzer, pressure switch, etc. Same beeper used for an overheat.

[Punch'Eau]

QR_BBPOST You should already have one for each engine. Take a look behind the helm. Mounted somewhere or tied to the harness should be an alarm horn/beeper/buzzer. If your key is on and the engine isn't running (no oil pressure), the alarm should be sounding. Same happens when you go to start the engine; turn the key to on and wait (delay circuit), the alarm should sound. If it isn't there's an issue somewhere; wiring, beeper/buzzer, pressure switch, etc. Same beeper used for an overheat.

Yes I saw them but I think I never heard them. They are suppose to sound when the key is at the ON position as long as the engine runs? And turn off when the engine turns and everything is normal right?

[Midnightsun]

My experience with Merc buzzers is they are annoying as heck. They sound off as soon as the key is turned and once the engine starts and oil pressure builds up they become silent.

It made my dog at the time freak out so I installed a timed delay on the circuit to avoid the hearing alarm before the engine was started. At one point in time, Merc also added some type of delay to the circuit to avoid what I explained above.

Bottom line is the circuit becomes live with the turn of the ignition key and not the starting of the engine.

[Viper]

Ya the old mechanical buzzers were hard to take for sure but coming on right away is going back pretty far. Eventually even the buzzers had a delay, still annoying when you had to leave the ignition in the on position to diagnose something. The newer beepers are easier to handle, loud but that's the point, it has to be louder than everything else going on around you should an engine issue occur.

[bud37]

Mine in 2001 were different, mercs , just beeped before start. Key on was the trigger even without start.

Perhaps consider something from the tach signal, not sure how but nowadays anything is possible.

I wonder are you having trouble with engine stalling when pulling throttles back to idle ????

[Punch'Eau]

QR_BBPOST Mine in 2001 were different, mercs , just beeped before start. Key on was the trigger even without start.

Perhaps consider something from the tach signal, not sure how but nowadays anything is possible.

I wonder are you having trouble with engine stalling when pulling throttles back to idle ????

Yes with starboard engine. I changed ignition module and 80% better but happened once again lately

[bud37]

I think if you do some more searches on this site you will find some fairly detailed threads discussing that sort of issue and how to resolve it. Combination of IAC motor counts, smooth operation, throttle body clean and undamaged with properly set throttle plate, IAC air port clean etc.

I had that same issue and it took a while to work thru it.

[Punch'Eau]

QR_BBPOST I think if you do some more searches on this site you will find some fairly detailed threads discussing that sort of issue and how to resolve it. Combination of IAC motor counts, smooth operation, throttle body clean and undamaged with properly set throttle plate, IAC air port clean etc.

I had that same issue and it took a while to work thru it.

I will take a look for sure. I already checked and cleaned the throttle body ( not better), changed the distributor cap (not better) and changed ignition control module (way better)
Thanks a lot

[Viper]

Ya I agree, you need to determine why she is stalling to begin with. The IAC is a good place to start, could also be an ignition issue. When did she last have an ignition tune up?