Voltage problem when starting..

rockstar01

Cadet
Joined
Apr 14, 2012
Messages
13
Hi

I have a 1999 maxum with the 5.0 2BBL mercruiser.

After sitting a while, i turn the the key to ignition, the warning buzzer comes on indicating no oil pressue. When I turn the key to start, the starter kicks on then immediately dies. Trying to restart gives no buzzer, or solenoid click.

After this happens, measuring the voltage at the fuse box under the the dash shows 9.5V on the ground and red/purple wires. ( which i believe comes from the engine harness )

When I pull the red wire fuse, which I believe is the radio. The voltage jumps up at the fuse box to 12.6v. Which lead me to believe the radio is maybe shorting the dash electronics, which is bringing down the voltage to supply power to the buzzer or the yellow and red slave solenoid power. but even with the radio fuse pulled, still no buzzer.

I have disconnected the engine harness and measured 12.6v on the red/purple (6) pin and the black (1) pin, on the engine side of the harness. which makes me think its not shorting on the engine side..

Also disconnected wires from the key switch and tested the S and I terminals ok.

I am at a loss as what to check next.

Also, this mercruiser doesn't have a 50amp breaker, I believe it had some kind of fuse which was removed when the starter was replaced by the previous owner.

Can any one advise on a method to troubleshoot?

Thanks RS.
 

tpenfield

Moderator
Staff member
Joined
Jul 18, 2011
Messages
18,453
My first thought is to have the battery tested. Could be the battery singing it’s swan song.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,291
Ayuh,.... or corroded wirin' connections,....
 

rockstar01

Cadet
Joined
Apr 14, 2012
Messages
13
Thanks for the responses, I started at the battery, did a full charge, and cleaned all the cable joints going from the battery to the engine block, perco switch etc, and tested after cleaning each one. It was the nasty grounding bolt at the port rear of the block. I guess the moral of the story is start with the basics.. Starts like a champ!

Next job, find out where my fuel sender is grounding out..
 
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