Mercruiser 4.3 ignition dead

Chrisbridgham

Recruit
Joined
Dec 1, 2012
Messages
2
I have a mercruiser 4.3 efi which I left accidentally left the batteries on for a couple of months unchecked. Of course the batteries went dead flat and after having charged them, the only things that work are the accessories, nav lights,
cabin lights etc. I cannot get any of the gauges or ignition to give so much as a whimper. does anyone know if there is a switch or fuse to stop power getting to the ignition.
 

ENSIGN

Lieutenant Junior Grade
Joined
Jun 21, 2009
Messages
1,179
Re: Mercruiser 4.3 ignition dead

There are fuses and a circuit breaker mounted on the engine.Is the lanyard switch turned on???
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Mercruiser 4.3 ignition dead

Have you checked (with a volt meter) to see if you have battery voltage on the red/purple wire on the ignition switch?
 

Chrisbridgham

Recruit
Joined
Dec 1, 2012
Messages
2
Re: Mercruiser 4.3 ignition dead

I've tested using a meter from the ignition and there is no voltage. It seems to go back to the motor somewhere. I'm tryin to track down the correct wiring diagram. I thought maybe there is something simple but the cct breaker and fuse on top of the motor seem to be fine.
 

fat fanny

Lieutenant Commander
Joined
Feb 9, 2006
Messages
1,935
Re: Mercruiser 4.3 ignition dead

With the meter start runnin a continuity test on the purple wire. It may require pullin the harness there is a hiden fuse in the harness and sometimes it's shielded with the same groumet as the large cannon plug. Look up in the adults only section (stickie) there is allot of good info on trouble shooting isssues such as these. Good luck and post back!
 
Joined
Sep 23, 2010
Messages
11
Re: Mercruiser 4.3 ignition dead

Did you put a new batterie or just recharged the old one ? The old one might be not enough strong even if charged. :cold:
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Mercruiser 4.3 ignition dead

We need the merc serial number off your engine. To many different efi system designs over too many years to give any kind of accurate information.
In general, start at the engine and start checking voltage on the red and red/purple wires. Here is a very basic wiring diagram that will give you an idea of how the power gets to your ignition switch. You may have a square fuse on the starter, or other fuses on the engine, and probably a fuse near the ignition switch. Without a Sn, it's impossible to say.

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