Fresh Mercruiser swap. No power

[matt167]

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]

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.

 

[matt167]

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]

Test light handy by chance or local store?
Mercruiser uses a starter slave solenoid to help activate the starter solenoid.

 

[matt167]

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]

What is item D I don’t recognize it

 

[Fun Times]

What is item D I don’t recognize it

Should be the 50 amp mercruiser circuit breaker,


Does yours have the 90 amp fuse at the starter?

 

[matt167]

I don’t see a fuse at the starter. Just the breaker and one in the wire to the ignition switch

 

[Fun Times]

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?

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

 

[matt167]

Anyone near you at the moment that might have a test light to barrow?

I’m back home now but I’ll bring one when i tackle it again.

 

[Fun Times]

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]

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]

I tackled it today after work.. helps if you plug in the big red cable

 

[matt167]

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