starting circuit wire

canadalooney

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Jun 7, 2016
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Its a little late as i have already purchased the wire 514gm motorcraft from ebay. 14 AWG gauge stranded. The wire previously was 16 and i replaced it with 16 but the new wire has more strands of thinner copper and i dont think it can handle the current when starting as it is getting warm to the touch and is having trouble cranking the engine( engine cranks fine if i bypass the cables). Battery outputs about 9.75 amps total circuit length is about 24 feet including ground at 12.7 volts. Positive cable going to motor and ground going to motor ( not battery cables i believe they are 12 gauge, again replaced the old wire with similar wire) and dont get hot.
 

F_R

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Say what? Let's start over. What motor are we talking about anyway? And exactly where are these 14GA wires going? There are very few circuits on an outboard requiring 14GA. And 12GA battery cables?? Way too small for battery cables on 99% of motors. Finally, 24 feet??
 

ondarvr

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Smaller strands tend to have less resistance, so it may work better. But F_R has good questions.
 

canadalooney

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Oh sorry forgot to mention motor it is a 1970 60 hp. Like i said the wires taht are on it now are the same size as the ones i replaced. 24 feet is the 12 foot positive cable and the other 12 is ground to the engine. 14 gauge wire goes from end of battery cable to the engine itself and supplies all of the engines power.
 

Crosbyman

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smaller strands have less of a cross section and resistance per foot is higher not lower !!! ex: 26 ga is a smaller wire than 16 ga. and it will not carry the load

the only way to carry higher current is to increase the cross section of a either a solid core wire or increase the quantity of individual smaller strands

house wires are mostly solid 14 ga copper for a 15 amp load at 110 V yet 12 ga cable is used for baseboard heaters for a max of 20 amps at 220 (110 each wire)


the main advantage of stranded wire is flexibility when it is needed . you would not want to jumper your car with solid core 6 ga wire whereas stranded
cable is very flexible and store (coils) easily under your car seat !
 

F_R

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What crosby said is true. It is the TOTAL diameter that matters (concerning ampicity), not the individual strands. More/thinner strands makes for better flexibility.

Anyhoo, that motor came with 6 AWG battery cables. But I seriously doubt they were 12' long. So, they probably should be 4 AWG because of the long length. As for the main power feed from the ENGINE END (at solenoid) of the + cable to the ignition switch should be 12 AWG. That thing has the battery CD ignition and that is finicky when it comes to voltage input. It isn't going to like smaller wire which decreases voltage. May give you starting problems.

I guess you know by now, smaller numbers mean bigger wire, and larger numbers mean smaller wire. Number and diameter of individual strands does not matter, it is the total diameter (AWG) that matters.....except for flexibility.
 

canadalooney

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Thanks for all the posts guys. Sorry if i was misleading the battery cables are actually only about 6 feet long. The cable that goes to the motor is 12 feet. Why would the motor use 16 gauge for most of the wires from the control box to tthe motor. The exception being 12 gauge from the positive pick on the solenoid. Has it been replaced? I measured the wire with strippers. Definately 16 gauge.
 

Silvertip

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Start over!!!! What wires are you talking about? 1) The wires in the motor harness between the engine and the control box OR 2) the two cables (positive and negative) that run from the battery to the engine? There should be no 12 gauge, 14 gauge, or 16 gauge wires between the battery and the starting circuit on the engine. Those are large gauge battery type cables. There should be a 10 or 12 gauge pair of wires running from the battery to the console to power the switches and other accessories up there. The control harness between the control box and the engine will have a mix of wire sizes.
 

canadalooney

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Alright you guys. The 14 gauge seems to have helped. However, the wire poitive wire is still getting fairly warm to the touch not hot though like before. The flywheel now rotates 2-3 times around as opposed to just once with 16 gauge with the pkugs out until it stops. I am still wondering how whoever got away with 16 gauge at first. I think i will stick with this 14 gauge for now unless it isnt turning the flywheel fast enough to start. What do you all think? 12.5 volts on battery.
 
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ondarvr

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From what I can get out your explaination is that the wires getting hot are the ones activating the starter solenoid, if those are getting hot it's either wired incorrectly, or the solenoid is not in good working condition. The solenoid itself shouldn't have a high amp draw.
 

canadalooney

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Riht now, from what i can tell, the only wire that is getting warm is the wire that goes from the end of the battery cable in the throttle box and then a distance of 13 feet into the motor where the rectfier is. If i bypass this wire with jumpers the motor turns much more rapidly. However, the wire previously on this motor was 16 gauge and it is right now 14 gauge. The consensus i am receiving is that i should upgrade my 6 feet of battery cable from the battery into the throttle box from 12 gauge to 6 gauge. Is that clrrect? Should i also see if i can shorten the wire from the throttle box to the motor so it is less than 13 feet?
 

ondarvr

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The heavy battery cables should not go to the throttle controls, they would go directly to the motor. A smaller wire goes from the motor to the ignition switch and back to the motor connecting to the starter solenoid.
 

ondarvr

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We are way off here, I don't see any heavy battery cables in the control box, just the normal wire (red) going from the motor to the ignition, it should have another similar wire on the same switch going back to the motor and connecting to the starter solenoid.

None of these wires should have any significant load on them at any time unless it's wired wrong.

You should have much larger wires going directly from the battery to the motor.

Post a pic of the battery and the wires connected to it.
 

canadalooney

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It is just normal 12 gauge wires. As stated before the wire is 6 feet long. Imagine you are traveling ln this wire... You go up to the control box 6 feet then connect to a 14 gauge cable that travels about 13 feet back to a bus bar on the motor. Same thing for the grojnd. Will oost pic tommorrow if still desired. Again, dont inderstand why the positive battery cable had a grey wire attached to it in the control box that led to this bus bar likewise for the ground battery cable and a balck wire. Someone had cut the vattery cables to the base of the throttle box, red and black wires. I assume they were battery cables.
 

canadalooney

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See the two red wires coming out of the throttle box on the left of the image? Yes? Those are the battery cables I replaced.
 
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