5.8 OMC Cobra Solenoid Melting

[Mbishop412]

I have a 1992 5.8 OMC Cobra. I had a fire last year. The solenoid melted, as well at the connection to the starter, and the positive battery terminal. I installed a new starter, new battery, new relay solenoid, new alternator, and new wiring. After approx 5 hours of normal operating, the solenoid cracked down the middle. The positive wire, to and from the solenoid, were extremely hot. I cannot figure it out. The solenoid is self grounding with a bolt through the motors frame. The only issue I see is the previous owner bypassed an ignition wire. Theres a straight wire from the ignition key to the solenoid. It doesn't not go through the neutral safety switch or harness.

This is the second time this has happened. Both times were after approx approxmins of constant full speed cruising. Stopped the boat. Idled. Turned it off, sat for a few mins, and when going to restart is has a very low, slow, drowning type of attempt to start. Does not start, check the compartment and see the solenoid relay terminals are starting to melt out and the wires are extremely hot to the touch.

Biat is a 1992 Four Winns 225 Sundowner

 

[HT32BSX115]

Howdy,

Welcome aboard!

Please post your model number.

a 1992 FW OMC boat could have the following engine/drive models.

584APLAMH 1992
584APLAMK 1992
584APRAMH 1992
584APRAMK 1992
584DPEAMH 1992
584DPEAMK 1992

584APLRGD 1991
584APRRGD 1991

If you don't have it yet, you need to obtain the correct OEM OMC (NOT SELOC, CLYMER, etc) service manual for your engine/drive model.

Once you have it, you'll need to use the wiring diagram to find the wiring error that is causing this problem.
You clearly have a situation that is liable to hurt someone if you don't fix it.

Once you post the model, someone here my have that manual and can help further!


Regards,


Rick

 

[Mbishop412]

Howdy,

Welcome aboard!

Please post your model number.

a 1992 FW OMC boat could have the following engine/drive models.

584APLAMH 1992
584APLAMK 1992
584APRAMH 1992
584APRAMK 1992
584DPEAMH 1992
584DPEAMK 1992

584APLRGD 1991
584APRRGD 1991

If you don't have it yet, you need to obtain the correct OEM OMC (NOT SELOC, CLYMER, etc) service manual for your engine/drive model.

Once you have it, you'll need to use the wiring diagram to find the wiring error that is causing this problem.
You clearly have a situation that is liable to hurt someone if you don't fix it.

Once you post the model, someone here my have that manual and can help further!


Regards,


Rick

I was able to get ahold of the wiring diagram from OEM omc pdf someone had. All the wiring seems to be correct. We have double and triple checked this. The only wire not ran originally is the ignition wire bypassing the neutral shutoff.

 

[Scott Danforth]

bad and corroded connections are the number 1 source of heat
undersized cables are the number 2 source of heat.

what you are describing is classic dirty or loose connection

if you have wing nuts on your battery throw them away and get real nuts

if your connections are not bright and shiny and clean enough for your wife and kids to eat off them, clean them.

 

[Mbishop412]

bad and corroded connections are the number 1 source of heat
undersized cables are the number 2 source of heat.

what you are describing is classic dirty or loose connection

if you have wing nuts on your battery throw them away and get real nuts

if your connections are not bright and shiny and clean enough for your wife and kids to eat off them, clean them.

Battery, cables, and clamps are all brand new. Clamps are marine rated. Tight and shiney new.

The solenoid relay is a 4 post relay. It is the only thing I could think that is maybe wrong. Could it not be grounding well enough? Or could a wire possibly be wrong I'm missing that's sending 12v to it as it's trying to reverse to charge the battery

 

[Scott Danforth]

new doesnt mean clean. did you clean them prior to installing

a 4-post relay needs a ground wire. a 3-post relay grounds thru the mounting bracket

 

[Bondo]

The positive wire, to and from the solenoid, were extremely hot. I cannot figure it out.

Ayuh,...... Welcome Aboard,...... Replace these 2 wires, 'n sand all of the connections to Shiny Clean Metal,.....

Even the new stuff,.....

As Scott is says, corrosion is resistance,.... Resistance equals Heat, with electricity,.....

 

[Lou C]

Is the starter bolted to a clean bare metal part of the engine block and are the battery negative cables attached to clean grounding points on the engine bell housing studs?

 

[Redrig]

Is the starter bolted to a clean bare metal part of the engine block and are the battery negative cables attached to clean grounding points on the engine bell housing studs?

Yes , to the OP certainly check grounds . I melted the positive terminal of a battery once due to bad grounds. It turned into a puddle of lead on top of the battery.

(only cranking , not running thank goodness )

 

[Mbishop412]

Thanks everyone. I was able to figure it out. The diagram a friend used that he was given was for a 92 omc cobra efi, not a carb version. The difference is where the starter wire attaches to the solenoid. It was in a different spot per the efi diagram, and not on the correct spot per the carburetor wiring diagram, causing it to short out!

 

[Lou C]

That was a good find! There are some wiring differences and also the diagrams are different for the Ford vs GM based engines. 5.8 is a 351 cu in Ford.