Correct Wiring on Ignition Coil

[jnbailey71]

When I purchased my boat the wire from the coil to the ignition switch was connected to the negative coil terminal and the positive coil terminal was connected to the side of the distributor. I have searched and searched and reviewed wiring diagrams, I cannot find any reason why the boat is wired this way. I am trying to believe that the previous owner had the boat running this way as he said he did.

Am I correct to say that the Negative side of the coil should attach to the distributor and the positive side should run to the ignition switch via the green wire?

I have cranked on the engine before realizing this but had no success turning it over because the fuel pump wasn't pumping. Could I have done any harm if the coil is indeed hooked up backward?

This is on a 58' Hercules K95 with a 12V system.

[evansjw44]

Coil wiring is positive to the battery (key switch) when the system has a negative ground; i,e, the negative terminal of the battery is connected to the engine block. That is reversed if you have a positive ground. As for damage -- no. The spark is weaker.

[jnbailey71]

Thanks for reassuring Jim- not sure what the guy before me was doing but I have a hard time believing he had it running hooked up that way....

Also- I found this 5A fuse (I think) behind the dash- connected to a white wire from the ignition then cut off in the wiring harness. Is this original- if so what where was it supposed to go to?

[Bilge Rat]

That is a circuit breaker, anyone's guess as to what it was wired to. At least it looks like someone used crimped terminals instead of just wrapping the wire around the screws. In 58, small boat wiring was pretty sketchy as compared to today's electrical requirements for safety. Typically two or three fuses and no fuse protection of the ignition circuit, which is shocking as that usually comes straight off of the battery. Battery can generate hundreds of amps into a short circuit and 14 gauge ignition wiring might be able to handle 15 amps depending on length. Although Ohms Law states that resistance of the wire will limit the maximum amps through it, the wire glows red before it burns open. Not good on a wood boat.

You should be able to disconnect and remove this circuit breaker. This coupled with the reversed polarity of the coil wiring would indicate a lack of proper wiring methods on the part of the previous owner.

[ClassOf56]

Isn't it possible that they set up a 12v positive ground system? That would explain the coil wiring.

As for the circuit breaker, that is a newer component, and is likely protecting something. People don't normally add them unless they had a problem, or were concerned about a potential problem. I wouldn't remove it unless you were very suspect of it failing. I would chase the wires and determine what it goes to at the very least.

[ClassOf56]

Sorry, I just re-read the post. If the circuit breaker is just running to a cut off wire, then heck yeah, you can get rid of it.

Josh, did you confirm which battery cable is connected to the engine block? Is it the + or the -?

[jnbailey71]

The negative was connected to the engine block so that tells me negative ground. That's the way I had the battery hooked up when I was cranking with the ignition switch wire hooked up to the negative terminal on the coil.

Glad to know I can get rid of the circuit breaker... trying to replace and simplify as much of the wiring as possible.

Another question while it is on my mind- is there any engineering to the spiraled end of the wiring closest to the generator and coils? When I go to replace all of this wiring I am wondering whether that is necessary?

[charlesquimby]

JN... When you say spiraled, do you mean coiled or pig-tailed? I usually cut wire a little long, install the ring terminal onto it, then wrap the wire five or six turns around a 1/4" round screwdriver shank to create a coiled or pig-tailed effect. This coiling reduces strain on the wire at the terminal, provides extra length for future work and, most important, absorbs vibration from the engine. CQ

[mfine]

Isn't it possible that they set up a 12v positive ground system?

Only Joseph Lucas would do that, and the corroded connections would cause enough other problems tht it would be obvious.

[cc-woodboats]

By 1958 all the US engine manufacturers had switched to negative ground.
only Joe Lucas {the Prince of Darkness} held out for a few more years
on the English vehicles.

[jnbailey71]

Charles- yes- attached is what I am talking about. What you are describing makes sense... I was thinking maybe the spiraled wire was in place to resist current but I couldn't figure it out because it doesn't make sense that any original instrument on this boat would interfere with the current. For the reasons you stated I now plan on doing the coiled wire.

[Bilge Rat]

Yep, the coiled up slack is just a way of neatly dressing the extra wire for any future need and helping to prevent a taught wire from vibrating loose while underway. The factory did this so if you're looking to appear "original" replicate it.

[jnbailey71]

Bilge Rat- I think for at least functionality I should keep this in place. Most of the time I believe that original specs were in place for a reason but with that in mind I also consider that new technology and engineering has been created to improve upon the past. This method certainly has practicality to it and is something i will do. So all it takes is wrapping the wire around a small shaft like a 1/4" screwdriver like Charles mentioned?

[charlesquimby]

Keeping original wiring is great for museum pieces. If you want original appearance, there are sources which supply such wiring with modern oil-resistant insulation over tinned, fine strand wire that meets current marine industry standards. If your wiring is original 1958 vintage, keep in mind that many times the jackets/insulation on older wire become brittle. I doubt seriously that circuit breaker is original 1958 issue. What many of us forget in the excitement of getting the boat into service, or during quickie repairs is that if our craft are underwritten for insurance purposes, or subject to a USCG "courtesy" inspection, wiring and ignition protection will be one of the first things held to scrutiny. I have participated in many ACBS judging activities, and have seen some really terrible wiring work on otherwise pristine vessels. I am hardly an expert in this field, and these are only my observations, but one thing I have always insisted on when wiring is no corner-cutting. Color-code the work, use tinned marine primary wire of proper gage, properly crimp and jacket all terminals, fuse all cicuitry, keep it neatly restrained and loomed, and most importantly, draw up a schematic as you go. My soap-box just collapsed... CQ

[cenger]

Piling on thread. For a 6v negative ground, when runnin at speed should the amp meter read on the negative side when charging?

[davidvn]

No Chris that's not correct if the system is actually charging then you need to swap the wires on the back of your ammeter

[Bilge Rat]

I use a pencil for the wire wraps and usually somewhere around 8 wraps.

[Bilge Rat]

Charlesquimby is correct on using proper marine rated wiring. Fusing is very important and as said before, extremely lacking in the original factory wiring. Important to note that solid wire should never be used on a boat, it cannot flex enough from the boat vibrations and movement and will fail. Always used stranded conductors.

[ClassOf56]

By 1958 all the US engine manufacturers had switched to negative ground.
only Joe Lucas {the Prince of Darkness} held out for a few more years
on the English vehicles.

This reminds me of an old joke for your friends that drive TR6 roadsters and MGB's.

Do you know why the Brits drink warm beer? Because they have Lucas refrigerators!

[Bilge Rat]

Some more Lucas Electrics jokes:

Alexander Graham Bell invented the Telephone. Thomas Edison invented the Light Bulb. Joseph Lucas invented the Short Circuit

The Lucas motto: "Get home before dark."

Lucas - Inventor of the first intermittent wiper

And yes, I have owned an MGA, MGB and worked on Midgets and a TR6.

[John DeVries]

Lucas Industries - the Prince of Darkness.

[mfine]

Did you know Lucas also made vacuum cleaners? It was their only product that didn't suck.

[Captain Nemo]

You guys are getting a little rough on old Joe. Hilarious .

[jim g]

Original Lucas replacement parts.

[Captain Nemo]

That's too funny, Jim