Ignition switch wire sizes and fuses

[fishykivette]

I have an OMC ignition switch that is six position with push to choke. My terminals read
C for choke S for start A for accessory M for ground B for battery positive
M raised for kill switch

My question is what size wire or fuse size do I need for the B terminal and M for ground? Will a 40 amp fuse on 8 gauge wire be sufficient?

 

[Daviet]

Re: Ignition switch wire sizes and fuses

What engine are you working on?
Doesn't the wiring harness on the engine have a main fuse in it?
Match the wire size that is in the harness, I think #8 wire would be overkill.

 

[fishykivette]

Re: Ignition switch wire sizes and fuses

Its a Johnson 88 special, from the motor is about a 12 wire and there is a fuse in the motor I thought i would need an external 40 amp breaker between battery and
B terminal on switch. This is what I've came up with so far C terminal to choke from motor with 16 gauge wire, no fuse.
A for accessory with a 14 gauge wire for console accessories (not CD player) to a fuse panel with 10 amp fuse distributed from there to GPS/Fishfinder
VHF RADIO, and accessory 12 volt plug.
M (non raised) for ground with 12 gauge wire to battery ground.
B for battery positive with 12 gauge wire to battery positive no fuse?
M raised magneto ground for kill switch 16 gauge ground wire.
S for starter solenoid with 16 gauge wire connected to motor starter solenoid wire. Non fused
B to either fused or non fused is really the only question I have i think the wire sizes are pretty accurate.
I have a separate battery for my accessories courtesy lights, bilge pump, Livewell pump, horn, navigation/instrument lights and CD Player. I have these accessories on a switch panel all fused with individual grounds excluding instrument lights. My tilt and trim are harnessed with plug. Hard to get that one wrong. My other question is do I need a large fuse or breaker for my positive wire from battery to fuse panel i have an 6 gauge wire going to distribution fuse panel from battery.

 

[hidef]

Re: Ignition switch wire sizes and fuses

Use the following links to help you rewire. The fuse in the engine protects the ignition switch. The accessory power is for the gauges do not use it for powering all of your other equipment. Run a separate wire from the battery to the console power distribution panel. If you want it switched you will need to use a relay.


http://maxrules.com/graphics/omc/wiring/REMCONTBOX.jpg
http://maxrules.com/graphics/omc/wiring/88_89_88_110.jpg
http://maxrules.com/fixomcwiringcodes.html

 

[daselbee]

Re: Ignition switch wire sizes and fuses

Exactly what hidef said.
The wires in the harness are 18ga I think. Certainly no bigger than 16ga.

The red wire with purple stripe is sourced at the engine and is fuse protected there with a 20 amp fuse.
The purple wire (switched 12v) should only power the gauges...tach for sure.

If you need amperage up front for stereo, aux power outlet, pumps....run a separate fused power line. I used #10 marine wire with a 40 amp inline fuse. Run a separate ground (same size) back to the battery too.

Marine wire is pre-tinned under the insulation so it will not corrode.