Jump engine harness to supply 12v DC to boat key switch for testing

Hello All,
Does anyone know the best way to jump the engine harness to supply 12v DC to boat key switch for testing purposes? I have my Merc 454 MPI out of the boat right now and before it goes back in I wanted to make sure all my pumps etc are working.

Thanks
Pat

Re: Jump engine harness to supply 12v DC to boat key switch for testing

While the engine is out, re-wire your boat so everything that is NOT engine related stays off the engine circuits. You should have the engine and 'non-engine' system completely separated. The only thing they should have in common is the battery and the battery switch.

To your original question. If power to get pumps etc working comes off the instrument feed and the engine is out of the boat, that makes it difficult. You need to connect positive and negative feeds to a couple of the pins in the end of the instrument harness. Alternatively connect battery power and ground directly to the instrument feed wires up in the instrument panel....

In a correctly wired boat, all that would still be working, even with the engine out.

Chris.......

Re: Jump engine harness to supply 12v DC to boat key switch for testing

achris said:

In a correctly wired boat, all that would still be working, even with the engine out.

Chris.......

Click to expand...

Yeah, that's what I thought but I had no juice when I tried it. I'll re check my wiring and test it again tomorrow.

Worst case I'll try and jump those pins...

Thanks guys!

Re: Jump engine harness to supply 12v DC to boat key switch for testing

I would assume your boat is probably wired correctly and not all coming off the ignition switch since it is new enough to have an MPI engine in it. So assuming that, you also need to make sure your negative wire is connected as well. Many times the main helm panels end up grounded on the back of the engine.