was just thinking....

[Dilligaf]

when i rewired my boat i used the 12v outputs on my 350mpi harness to feed all the power on my boat. should i have connected my main "feeder" to the battery to feed everything instead of off the engine harness?

[Dilligaf]

75 views ... no responses???? someone has to have an opinion

[hermco]

What is a 350 mpi?

[lost2a6]

I would have run a very heavy gauge wire to the battery switch; you never know what sort of accessories you are going to add in the future. On my Seavette I ran 2 gauge positive and negative wires to distribution blocks for my power supply. Of course this was for my two amps and all of the power supply.

[bigeasy1]

I assume you mean a 350 C.I. multi port injected I/O.Not many of us I/O guys.

I'm not sure of the correct answer,but when I wired my 350(an older one)I only ran the 12 volt gauges and ignition off the wiring harness.
I ran separate wires from the battery switch to a couple of + & - blocks in the stern,and ran my grounds for the stuff in the stern like tabs,pumps,downriggers,and blower off of them.
I ran separate + & - wires off one block,to the front where I have a panel at the helm with eight switches,for the remaining stuff like lights, electronics,tabs,wipers,spreader lights etc.
I think it may be a bit easier to trace any electrical problems with a dedicated 12v supply.In my case the wiring harness is tucked up into the gunwale where it would be very difficult to get at,if I had a wiring problem.

I ran #4 gauge tinned wire from my battery switch to the blocks.I also ran #4 gauge positive and neg.wires from them to the helm.
I used mostly 12 or 14 ga. wires to each item and switch at the front.

[Blue_Heron]

should i have connected my main "feeder" to the battery to feed everything instead of off the engine harness?

The short answer is "yes". The hot wire in the engine wiring harness is intended to feed the ignition circuit and gauges. Unless you have a very light load on your electrical system, you are probably overloading that wire's current carrying capacity.

Like Lost2a6 and John123, you should run a separate wire to a fuse block to feed accessories like pumps, lights, radios, etc. The wire size from battery or battery switch to fuse block will depend on your total electrical load. And just like in your house or car, all wires should be protected by appropriately sized fuses.
Dave

[Dilligaf]

the reason i ask is because when i did it my manual said that the power feed comeing from the wireing harness is good for 40 amps. but most people i see hook up to the battery. 350mpi = Mercruiser 350 ci multi port injection.

[Blue_Heron]

...the power feed comeing from the wireing harness is good for 40 amps.

Well you learn something new every day. My Merc outboards don't have a power feed in the wiring harness. The hot wire is fused at 20 amps and only powers the ignition circuit, gauges, and power trim solenoids. Unless you have some pumps or winches that draw a lot of current, the 40 amp feed in your Mercruiser harness will probably power your accessories without problems.
Dave

[Bwright1818]

What some guys do....and what MUST be done on DTS units, is to wire in a relay. The relay closes when key-on power is applied to it. Then, accesory power from a seperate main buss passes through the relay. Again, this is only if you want things to be on only when the key is on. All other things should be wired to an independent main buss, with its own main fuse or breaker and branch fuses or breakers. Wiring things through the engine harness is just giving yourself another way not to be home in time for dinner. Let the engine do its own thing.

[Dilligaf]

aight so i should leave gauges and ignition on harness power and everything else on battery power then right...