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Spectra 20 Wiring... Help?

CorporatSpectra

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Ive got a 77 Spectra 20 jet and ive got a couple wiring issues. I cant seem to find a good diagram anywhere for the old rig. Would it be too much to ask for someone to post a pic of the main wiring junction plate that sits on the back of the engine above the flywheel cover??? thanks!!
 

74 spectra20 v-drive

74 spectra20 v-drive
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I don't know if there ever was a wiring diagram posted for these as they have been out of production for so long most just make up a custom to them set up. Not a lot going on with these for electrical but there you can find a lot of diagrams on the web. I personally don't like the fuse block on the engine just an aesthetic think for me. I put everything behind the dash on mine.
 

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old rigger

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These diagrams have been floating around for a long time and different sites put their name on them, but this is basically how your boat was wired. All builders used the same jet basic wiring back in the day, and for decades after, and all engine suppliers used the same little junction block (they weren't fuse panels) mounted on the rear of the engine and we all bought wire looms from the same handful of suppliers. Some made their own looms but not many. (My first job was making wire looms for my dad when he started rigging as there were no suppliers yet. I got to stay up late and watch TV if I was making dash looms on the little jig he made me. I was about 9 or 10)

Hope this helps.
fullsizeoutput_1da5.jpg fullsizeoutput_1da6.jpg wiringdiagram.jpg
 

johnny79

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Ive got a 77 Spectra 20 jet and ive got a couple wiring issues. I cant seem to find a good diagram anywhere for the old rig. Would it be too much to ask for someone to post a pic of the main wiring junction plate that sits on the back of the engine above the flywheel cover??? thanks!!

Here is a pic on the back of my 460 in my 76 Spectra 20
 

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AzGeo

Fair winds and following seas George.. Rest Easy..
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We always made our own harnesses, we always used thicker wires than the required "minimum gauge wire" .

Even though (by law) all the wiring must be "secured" every 12", the wires and harnesses will always "flex and move around" if you actually use the boat . Thicker wire is more heavy, but also has more strands with less failures .

Most diagrams show not only 'gauge' of wire but also the proper color for a particular circuit, but I see that your current wiring has "wrong colored wires" in a number of places already, so how do you want to proceed ?

Fix the current (pun) problem, or rewire the whole boat ?
 

AzGeo

Fair winds and following seas George.. Rest Easy..
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The top is black, ground .
2nd is red, battery.
3rd is also red, but orange on one side, this is charging .
4th is white on one side and yellow with a red tracer (correct colors) which is cranking .
5th is purple, which is ignition ON (running position of key switch).
6th is light blue, which is oil pressure .
7th is tan, which is water temp .
8th is grey, which is tach signal .

Plane red is normally UNFUSED .
Red with a purple tracer is indicating that it is fused .
Fuel tank sender (s) should be pink and second tank would be pink with a white or black tracer .
Bilge pump is dark brown .
Bilge blower should be yellow (in later boats it is often orange) .
Running and dash lights are often dark blue .
Some will use green as a 'bonding strip', which is a ground .
New NMMA guidelines have been using yellow as a 'bonding strip', as in boats like Bayliners .

This is the tip of the iceberg ............
 

boatnam2

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I have a question, so the plate the 10 pin plug in on, the 2 red wires with boots behind it are for what? And does it matter how they are put on, i went with the this wire look like it fits here, not sure its right. this is on a 1979 spectra with a merc 260.
 

wzuber

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These diagrams have been floating around for a long time and different sites put their name on them, but this is basically how your boat was wired. All builders used the same jet basic wiring back in the day, and for decades after, and all engine suppliers used the same little junction block (they weren't fuse panels) mounted on the rear of the engine and we all bought wire looms from the same handful of suppliers. Some made their own looms but not many. (My first job was making wire looms for my dad when he started rigging as there were no suppliers yet. I got to stay up late and watch TV if I was making dash looms on the little jig he made me. I was about 9 or 10)

Hope this helps.
View attachment 573019 View attachment 573020 View attachment 573021
how cool is that? very, very.... what a great way to kick start a young mans interest in boats, electronics, mechanics etc.
 
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