No electricity in 350 Mercruiser MPI

[Ahmed Al Dossary]

Hello all,

After overhauling the engine, it no longer turns or any of electricity reaches the engine or gauges. Any recommendations on what to inspect?

 

[scoflaw]

Power flows from the battery to the 90amp breaker at the starter. From there red wire goes to the 50 amp breaker on top of the engine and leaves as r/p which goes to the helm, alternator and the slave solenoid.

Get a test light or dvm and check at those connections. Don't forget the ground from battery to the engine block

 

[skibum]

Is it grounded properly? If you've got nothing, it's a candidate.

Sounds similar to a problem my best friend's brother had back in the early 80s. He rebuilt a 289 in a 65/66ish Mustang (I think - I was a Chevy guy back then) and tried but failed to get it to run for 3 days. He eventually asked his brother to help, and it turned out that there was engine paint where they bolted the ground strap on. Cleaned it all up and she fired right up.

Edit: There are most likely several wiring harness connectors on that engine. I'd also take a second to disconnect each one and look at the pins on one side to make sure that there aren't any bent one. The little pins and the little sockets in the plugs are usually pushed into the connector from the back when they are assembled. If you see any pins that look shorter than the others, pull them out with needle nose pliers. Check the other side of the connector to see if all of the little metal sockets are visible and seated fully meaning ask closed to you as they can get when you are looking into the end of it. Sometimes, just unplugging and reconnecting the harnesses can fix a gremlin.