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Ignition wiring question for an old boat

jaybirdnwa

New member
I have a 1967 IMP Inca Cuddy Cabin that I am trying to wire a new ignition switch. The wiring under the panel was very dirty mess. The ignition switch was taken off and replaced with another but the wiring diagram was lost and now I'm unsure of what wire goes to what post. How is the best way to identify which wire goes to which post. My switch has 4 posts: B, I, and 2 ACC's. I am new to this and would like to try and learn to do this myself instead of taking it to someone do for me. So any help would be appreciative.
 
See below...

IDENTIFIERFUNCTIONWIRE COLOR CODECONNECTS TO
BBATTERYRed with Violet stripeBattery positive via fuse
A or IACCESSORY or IGNITIONVioletAccessory loads; engine ignition
SSTARTYellow with Red stripeEngine starter solenoid coil
CCHOKEViolet with White stripeEngine primer solenoid coil
MMagnetoBlackEngine chassis or battery negative
M (raised)MAGNETOBlack with Yellow stripeEngine ignition kill circuit
 
Thanks Chawk_man,

After reading other posts and different websites, I wired it and got it to turn over. I had read these tables before but the problem is that none of the colors found in these tables match up to my wiring (brown wire was used to come off the battery). At some point, this boat needs new wire, but I am not ready to tackle that yet. Thanks for the help.

Jaybirdnwa
 
Roger that. I know what you mean. The only thing that works consistently on an old boat is its owner.

When you are getting ready to re-wire, post it, and I'll jump in to give you a few lessons learned from experience I've had. It's called "learning the hard way."
 
That's for sure, but it is fun to work on. I will definitely post here when I get ready to tackle that job. How involved is that job? Can it be done in a weekend?
 
Probably so if you get all the materials you need assembled beforehand. The most important thing is to order the right wire - it sould be tin coated and made specifically for marine applications. You can get rolls of different colors from West Marine and other marine supply retailers. Get plenty of red and black. I usually use 14 gauge for most applications, except for heavy loads like a windless (10 gauge) or electric trim tabs. Get a good pair of cutters and crimpers. Use heat-shrink connectors. Get plenty of wire straps. On my current boat, I ran a positive and negative pair of heavily insulated 10 gauge wires directly from the battery switch to the back of the console and connected to a large terminal strip. That allowed me to tap into a clean power source for the many items in and around the cabin console - electronics, gauges, horn, lights, etc, etc. If you plan to wire in a communications network (NMEA 0183 or 2000) plan that out ahead of time and make sure you have all the right connectors and wires. You'll need a minimum network to hook in your DSC equiped VHF to your GPS.
 
If the "Standard's" color doesn't match what you have, look for the device at the far end and then note the 'active' wire's color and amend your existing drawing...you are creating the drawing as you go so you don't have to repeat the learning exercise, right?

the Marine grade wiring can be obtained (given enough lead time) economically thru various sources. Only change I'd suggest to CHawk's list is to get separate connectors and "double walled" heat shrink tubing. The 'plain' crimp ons are much cheaper than those with the tubing attached. the tubing type mentioned has an adhesive lining the inside of the 'regular' (single walled) tube that helps exclude water, moisture, and other corrosive things. Trade is that it does take more time to add the tube to each connector. Finally, use liquid neoprene to finish all the connections that you make. I've seen boats that I rewired 30 years ago and electrical problems (with the wiring) just don't exist.
 
Thanks for that input. The wiring underneath the instrument panel is a complete mess with wires spliced together with electrical tape. So it doesn't make me feel very confident so I'm going to attempt to re-wire from the harness. I will post pictures shortly and any advice would be appreciated.
 
Makomark - Yep, I forgot to mention the liquid neoprene. I use the stuff called liquid electrical tape, or something like that. Also, you are correct on using the shrink wrap on standard connectors, they normally work fine. However, I've notice that the ones with the shrink-wrap already attached seem to be heavier duty, so I still prefer those when I have them.
 
OriginalWiringfromOMCV_8.jpgOriginalWiringunderPanel.jpgIMG_3476(reduced).jpgIMG_3477(reduce).jpg

Ok, after looking at the mess I have under the panel, I have decided that it needs new wiring that is clean and organized so maybe next time either me or someone else doesn't have to figure this mess out. But, this will be my first time attempting this so I am posting a few pictures here of the original condition of the job and hopefully, someone can offer advice. My plan is to not rewire from the engine to the panel but just the panel (the engine wiring looks to be in pretty good shape and somewhat organized).

The first photo is the set of wires coming into the panel from the engine. The second photo is the wiring mess underneath the panel. The other 2 pictures are the male/female harness that go together that go to the ignition switch.

In picture 2, what is the black bar attached to the steering column and would it be a problem if I take it out just to give myself more room to see and work?
 
Let's back up a minute. What engine does this wire harnes come from? (I think most of those early Inca's had something like a Crusader 220, which is equivalent to a GM 305.) You will likely need to identify the function of each wire coming out of the wiring harnes from the engine, based on its color, or based on what it is connected to on the engine. If it is an old Crusader or GM, that will be pretty simple to do. They are not very complicated. Most of that stuff is posted on the web or the owners manual for your particular engine. Let me know if it's a Crusader, because I think I still have the wiring diagram somewhere in my files.

I would start by tracing each of the wires in picture 1 back to the engine to make sure nothing has been spliced into them and that the color coming out of the engine is the same color coming into your console.

Picture 2 looks like it is just the brace for the helm. I see no reason you can't temporarily remove it to get more working space.

Pictures 3 & 4 - Replace that plug with a new round one that has the same number or more pins, and has a moisture seal all around - at the plug interface and on each end where the wires enter the plug. Use plenty of liquid tape (neoprene) on each end to form a good moisture barrier. Before removing that plug map each of the wires in both directions and determine it's function. Write it down and take plenty of pictures.

Your biggest challenge is going to be wiring up the ignition switch correctly so it incorporates the kill switch on your safety lanyard, and your alarm buzzer. If those two items are currently working, then simply duplicate the way they are currently wired. Also, if you have a tachometer that is working on the current engine, I would leave that alone unless the wire is in bad shape.

Finally, before digging into this project, do yourself a favor. Get down next to the engine and get a wad of paper towels and rub them over the bottom of the oil pan. See if you have any oil on the paper towels. These engines were notorious for rusted out oil pans. If you see oil on the paper towels, use your fingers to gently probe the bottom of the oil pan. If it is soft, or highly scaled, you will likely need to pull the engine and replace the oil pan. If not, then look for the source of the leaking oil. It may be just the valve covers, which were also notorious for leaking. For most engines, they make a cast aluminum oil pan that will not rust out.
 
Thanks C-man for the advice. The engine is a GM 305 (I think). When I bought the boat, I was told it was a GM 350. How can I make sure. I know it is a V-8 and so far it has been pretty simple to work on. I had already planned to trace each wire back to see where it is hooked up to the motor. But I will begin with the oil pan test first to see if there is a problem there. I am assuming it is OK because I just had some work done on it by a mechanic and they changed oil in it for me. I have noticed it leaking at the tilt mechanism housing on the sterndrive which I opened that up to find that there was no gasket. But I will repost about that later.

Thanks for your advice and if you have a wiring diagram that will help let me know. I do have a Selocrepair manual for OMC Stern Drives 1964-1986 with some wiring diagrams in there. But any other information/advice you have is welcome as I am a newbie at this but am willing to learn although I grew up working on point ignition cars with my dad so much of it is not new. I will post pictures as I go. Thanks again.
 
Can't help you much with determining whether it's a 305 or 350. Some of the newer blocks had 305 or 350 (or whatever variation stamped on them.) Blocks are about the same size. Here is what I found on the web (edited.) "Only real way to tell is get the suffix code and casting # off the block and look it up. Suffix code is on front pass side of engine, in front of head on machined pad. #'s are stamped into pad. Clean grease/dirt off with carb cleaner, wd-40, etc and a rag before looking. Casting # is on rear driver side of block, on flange that transmission bolts to. #'s are raised so a little easier to see, but will still need to clean it good. Once you have the #'s go to www.mortec.com to look them up and see what you have."

Don't assume the oil pan is okay because someone changed the oil. Typically, they thread a tube down the dipstick hole and pump it out.

I searched my computer files and did not find the wiring diagrams. So I guess I deleted those before I switched to a new computer. Sorry 'bout that. However, the good news is that the 305 (5.0 liter) and the 350 (5.7 liter) are so similar in design and operation, there is a ton of information about them on the Web. Both engines have been around for a long time. If you ever need to replace the engine, the Jasper MARINE rebuilt short block goes for about $2,500 and carries a 1 year guarantee.

Based on my own experience running a 25 ft boat I/O with the 305 in a saltwater environment, and working on 305's and 350's as a shade tree mechanic, here are the things you need to consider and watch.

Based on your location in Arkansas, I assume you will be running exclusively in fresh water, so there is no great need for a closed cooling system and heat exchanger. However, if you have a closed cooling system whereby the engine coolant is cooled by running raw water through a heat exchanger, your engine will last longer because the chemicals in the antifreeze mixture helps retard rust and scaling.

If you don't have a Racor fuel-water seperator, install one. This will keep water out of your fuel and make for a better running engine.

Occasionally run a concentrated mixture of Sea Foam or other decarbonizer through your engine. You'll need an external gas tank hooked up to your fuel line, which is easy to do. Follow the directions on the can for decarbonizing. You'll probably be amazed at how much junk comes out of your exhaust. If you want to keep the engine and carb in really good running order, add Sea Foam at every fill up. Also, if you are using ethanol-laced fuel, and the fuel will be sitting in the tank for extended periods of time, add a fuel stabilizer like marine Sta-Bil, or Startron.

Typically your caborator will be the source of most of your running problems. Learn how to remove it and clean it, and install rebuild kits. Depending what type carborator you have, will make this task easy or complicated. Personally, my downfall has been the Webers.

Make sure your coolant temperature gauge and oil pressure gauge are working properly. If you don't overheat the engine, and the oil pressure stays within specs, that engine will run for a long, long, long time.

If you have the standand point-breaker ignition system, consider replacing it with a sealed electronic ignition system.

Regularly inspect your manifolds and risers for leaks. If you ever have to replace them, take your time and use a lot of PB Blaster and heat. You'll still have a good chance for snapping off a bolt, so when you replace them be sure to use liberal amounts of anti-seize grease on the bolt threads.

Inspect you OMC outdrive regularly, especially the bellows connection - a broken bellows has sunk a lot of I/O boats. Check the I/O oil regularly for water incursion.

That's about it for a Sunday morning. If Makomark is still monitoring this thread, I'm sure he will jump in with additional observations and advice, since he is much more experienced than I am.
 
Whew, that is a lot of information which is valuable but right now, I just want to get all the wires free from splices and electrical tape. The person who wired this boat the last time seemed to take the challenge of wrapping the entire electrical system with 1 piece of electrical tape. The electrical tape is melted on and it is a big mess. I was wondering if there is a problem in removing all of the electrical tape and wrapping them with cable ties and them placing that in a flexible tubing (will this stuff stand up to the heat?). Some of the electrical connections are showing bare wire and are not done correctly so rather than replacing all of the wiring, I am repairing the connections with a weatherproof/integral heat shrink Butt Connector. Let me know if you think I should go in a different direction.
 
That sounds okay as far as it goes. Definitely get rid of the tape. However, your basic problem is that you don't know what kind of wire was used for the various connections and splices. You want to use only tin plated multi-strand wire. You can tell if it is tin plated because each individual strand will be a dull silver. Copper wire corrodes in a marine environment and the individual strands will turn black or a very dark grey. Don Casey had a good write up on all this. See http://www.boatus.com/boattech/casey/electrical-connections.asp
 
Well, it doesn't appear that it is tin plated multi-strand wire so I guess to do it correctly, it should all be replaced huh? Take the picture for instance. This doesn't look to be a safe connection to me and the wires doesn't appear to be tin stranded. These wires are a group of wires that lead to a harness. Do they sell the harness for this already complete or can I make a new harness? If so, is there a place on the web that explains how this is done? How would you advise this wire be repaired?

Sorry for all the questions but this is my first attempt at this kind of job. I'm not afraid to tackle it, just want to do it correctly.
IMG_3482.jpg
 
Well, that picture is not that bad. Whoever wired it used neoprene to insulate the wires from chaffing against the metal bracket. A plastic hole sleave would have been a better solution.

You can probably purchase the harness, but that is problamatic, since you are not exactly sure of what engine you have. Typically, you will have one of two types of set-up. The first will be a hardwire situation, where each wire off the engine runs directly to your console - ignition wires, heat sensor wire, oil pressure wire, tach wire, etc. The other situation is when each of the engine function wires run into a large multi-pin connector plug. That plug is then mated to a multi-wire plug that takes the wires to your console. At the console, you will have another multi-pin wire with leads to the ignition, gauges, warning buzzer, and so worth.

Personally, I would make my own. That way, I know exactly what I am dealing with. I think if you do some Google searches, you'll find a discussion on the setup. Start by typing in something like "Marine 305 wiring harness".

The bottom line is that you are going to need to spend some time unraveling what you have and how it should be wired up. It's a great learning experience and you will build a lot of confidence in your engine and setup.
 
Jay, I just took a quick stroll through your thread here and have a few suggestions for you. BTW, I do have many years (40+) of working in this field, including marine electrical.

I would avoid using an ignition switch that offers an Accessory side. We don't need a key switch to provide power for VHF radios, GPS, etc.

Typically, these do not require a key switch function, and are best if powered via their own separate individual power source... IMO. In fact, I have never owned a boat whereby the ignition key switch powered these, nor would I care to.

What I prefer to see would be a new, fresh dedicated circuit run forward to a new, fresh dedicated fuse or breaker panel. It does not need to be excessive. 6 new circuits will usually provide all that you need for GPS, VHF, DS, FF, etc.
This completely removes these loads from the OEM Engine/Hull harness.
When the hull is powered up via the MBSS (main battery selector switch) these will be powered and ready to go.
When we leave our boats, we typically turn the MBSS to OFF, so no key switch needs to be involved.

Chalkman, I believe that a Windlass will require much more than 10 ga. We'd be getting into cable, not wire, for a Windlass power circuit.

I have to agree with Mark, and disagree with using the pre-applied shrink tube wire fittings. The crimp tool (even high end tools) typically disturbs the shrink material, and when heat is applied, the shrink material fails right at the crimp. While it may sound like a good idea, I won't use them!
This is from my actual experience having seen these fail.
If you like the shrink tubing idea, I'd recommend that you use bare wire fittings, and apply separate shrink tubing.
That is the correct method, IMO.

You may also want to eliminate the push-plug fittings, and use a ring terminal junction block with protective cover. The little harness fittings can fail due to eventual corrosion.

This can become a large undertaking, but will reward you in the end. Have fun with it. :D
 
Rick - Okay on the windlass wire - I think it is actually larger. It's a Horizon 600 and the spec sheet specifies 8 gauge. I matched the wires coming out of the windless, so that should be okay. I thought they were 10 gauge.

What I did was run a heavy duty highly insulated dual cable (battery cable) from my battery switch to a bus behind the console, then pulled power and ground off of that buss for power to VHF, GPS-MAP, depthfinder, windlass, lights, horn, spot light. etc, etc. Each of those is wired through a fuse panel using auto-type spade fuses. The only thing I used the accessory terminal on the key switch for was the lights on the gauges. This sounds similar to what you are recommending for Jay.


I have not had any problems with the pre-applied shrink wrap connectors, at least as yet. I think either method works.
 
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