4.3 Merc just died

[JimS123]

Carbureated 4.3 mercruiser alpha 1. 2007 model with about 60 hours. No problems thus far.

We were running out in the lake at dusk at about 3000 rpm when the motor just died. The only thing runing at the time were the running lights. It would not restart or even turn over.

The ign switch fuse had blown, but it still would not turn over after it was replaced. The battery is good. All of the other electrical itesm do work...i.e. the blower, pump, lights, cabin lights, radio, etc.

Where should we start to look for the problem?

TIA

 

[Limited-Time]

Re: 4.3 Merc just died

I would make sure the engine is not seized before I went to far...................I'd pull the spark plugs and try to turn it over by hand.

 

[180shabah]

Re: 4.3 Merc just died

Break out the DVM and start varifying wire integrity and connections.

 

[180shabah]

Re: 4.3 Merc just died

One more thing... it is in neutral, right??

 

[JimS123]

Re: 4.3 Merc just died - UPDATE

Re: 4.3 Merc just died - UPDATE

Ok, we found that the main 50 amp breaker was thrown as well. We located a red wire that was run too close to the engine and it had melted and grounded out. So, fixed the wire and now the engine starts and runs.

New problem - now when you turn off the key the engine won't shut off. When the key is switched off the radio and other electrical items go off, but the only way to turn the engine off is by hitting the 50 amp breaker.

Now where do I look?

TIA

 

[JustJason]

Re: 4.3 Merc just died - UPDATE

Re: 4.3 Merc just died - UPDATE

be looking at your bad alternator.......

 

[Don S]

Re: 4.3 Merc just died - UPDATE

Re: 4.3 Merc just died - UPDATE

The first place to check is the ignition switch. With the main circuit breaker reset, remove the purple wire and see if there is power on the switch terminal with the switch off. Also check the purple wire and see if it has power.
If the switch doesn't have power, but you do have power on the wire, Disconnect the 2 wire terminal on the alternator (The one with a Red/purple wire and a purple wire in it)
Then see if you have power on the purple wire you have disconnected at the ignition switch.

 

[achris]

Re: 4.3 Merc just died

Had exactly the same problem on my previous V6. You may find that the purple ignition wire is shorted to one of the main red wires somewhere near the original damage.

Chris.............