Fresh Mercruiser swap. No power

matt167

Captain
Joined
Sep 27, 2012
Messages
3,837
Pulling my hair out. Took a running 3.0L alpha one gen one out of a well rotten four winns. Pulled entire wiring out and I have no power at the key switch.. the mercruiser harness is still in the four winns dash panel. Nothing registers. No volts, no crank, no life. The breaker on the motor is not tripped. Where should I look?

I should edit. The back of the boat is completely wired in and hooked up.. I was baking in the sun standing on my head under the dash trying to get the dash panel out when I decided to just leave the four winns panel in place for a test
 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
8,879
Is there power at the breaker 2 red wires?

Is there 12v power from the battery to the engine starter?

Main wire at the alternator has 12 volt power?

Wiggle the main engine wiring harness.

Some 3.0's have while some 3.0's don't have a 90 amp fuse at the engine starter.

1716773601866.png
1716773707897.png
 

matt167

Captain
Joined
Sep 27, 2012
Messages
3,837
I didn’t have a DVOM with me at the boat.

I disconnected the main harness several times and re inserted it.

What does that solenoid do that is right under the big plug?
 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
8,879
Test light handy by chance or local store?
Mercruiser uses a starter slave solenoid to help activate the starter solenoid.

1716774134455.png
 

matt167

Captain
Joined
Sep 27, 2012
Messages
3,837
Yeah I have test lights and dvoms. Problem is I don’t work near my tools. It’s at my FILs so I literally have to bring what I think I’ll need, and electrical testing wasn’t on my radar today.

But that diagram will for sure help me dial it in. Thanks.
 

matt167

Captain
Joined
Sep 27, 2012
Messages
3,837
I don’t see a fuse at the starter. Just the breaker and one in the wire to the ignition switch
 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
8,879
I don’t see a fuse at the starter. Just the breaker and one in the wire to the ignition switch
Anyone near you at the moment that might have a test light to borrow?

:D

How to make your own test light / circuit tester. DIY incandescent test light.​

 

Fun Times

Moderator
Staff member
Joined
May 16, 2009
Messages
8,879
I’m back home now but I’ll bring one when i tackle it again.
See post number 9 again for a bit of humor / worst case scenario. :)

Always carry a test light in the car as it's an easier way to check fuses, etc. on the quick. :)
 

matt167

Captain
Joined
Sep 27, 2012
Messages
3,837
lol my coworkers test light is just an old bulb socket. Another coworkers is an actual GM certified test light, but the Harbor freight one I have is just as good.. GM calls for test lights quite a bit in circuit testing
 

matt167

Captain
Joined
Sep 27, 2012
Messages
3,837
I just transferred the gauges/ harness into the boats original dash panel.

The 4 Winns panel had the fuses wired into the volt meter stud. Can I run a wire from that stud to a blue sea systems fuse box? The old system ran power to the fuse box ( old style ) from the back of the boat. A LOT of wiring that I don't know what is running under the gunnel and in the back. I'm gonna get the bilge pumps working, Nav lights, anchor light and the blowers and worry about extra stuff later

Also, The volt meter seems to be hot at all times with the battery connected. Is that correct? I really can't remember f
 
Top