1994 350 in a 1982 boat wiring problem

[ryanwilson277]

Okay so i am new to this forum with an issue thats making me pull my teeth out. i own a 1982 checkmate eluder that i recently installed a mercruiser 350 with thunderbolt ignition from a 1994 boat. all that i had to remove was the big prong for the orange wire in the wiring plug (i know i removed the correct one lol). so when i went to test start the engine i had no spark out of the tower on the coil. i had done all of the ignition test per mercruiser and i dont get any voltage from the red/white wire. i borrowed a separate wiring harness/ ignition switch used to test run the engine when out of the boat from a mechanic and wala! i got spark. so now i know i have an issue on the boat side and everything on the motor is good. so i started tracing wires and looking at the gauges and from what im seeing everything looks to be hooked up correctly per what the books wiring diagram illustrates. so what i was thinking is where my 4 accessory switches are im having the issue.

okay so i need to mention that with the boat wiring plug hooked to the engine with the key on i dont get voltage at the green/white or the red/white, but i do get voltage at the positive terminal on the coil. and also get voltage at the negative side of the coil. so the odd part is that when i disconnect the two grey wires from the negative post on the coil my navigation lights go out? so okay, im thinking my problem is at my accessory switches/light switches. so i disconnect all the wires from the switches and re check for spark. nothing. so then disconnect the radio and all other power wires in the ignition switch so the only thing hokes up is the purple, red wire, and yellow with red stripe. still no spark.

i really would like to fix this and get this boat running without buying a new wiring harness. if any more information is needed i will try my best. i apologize for my typing and run-on sentences, i dont use the computer much lol. any tips on where else to start would help. thank you

 

[Bondo]

so the odd part is that when i disconnect the two grey wires from the negative post on the coil my navigation lights go out?

Ayuh,.... Welcome Aboard,..... While it may not fix All yer problems, I believe I see 1 Big problem,.....

Yer dash don't have a solid Ground,....

The nav-lights, 'n all the accessory circuits should run both (+), 'n (-) to, 'n from the dash, independent from the motor,...

 

[ryanwilson277]

okay, thank you. i will give that a try first. makes sense to why the lights go out when removing the grey wires on the coil?

 

[ryanwilson277]

Okay so looked into the serial number of the engine I have and turn out it's actually a 1997 350 with thunderbolt V ignition. I was wondering about my wiring, I have two thick black wires going to the plug for the engine but on the guage side I have one thick and one thin black wire coming out of the harness, do

 

[Bt Doctur]

The only diagram I find with a large orange wire used an ammeter gauge. If you eliminated that wire you removed the 12v feed to the wiring harness
What engine was in the boat originally? All the harness has is 1 large black wire

 

[ryanwilson277]

The orange ammeter wire has already been cut and removed under the dash. The boat originally had an 82 350 with log style risers (another problem I have)

The boat is a 1982 19ft checkmate eluder. Also I noticed when using a test light hooked to the positive terminal of the battery when I touch one of the grey wires hooked to the coil I don't have ground but the other wire I do have ground.

 

[Bt Doctur]

Stop testing that way , this should be you old wiring setup

 

[Bt Doctur]

and your trying to plug it into this pattern

 

[Bt Doctur]

 

[Bt Doctur]

check your messages

 

[Bt Doctur]

Comparing the plugs number they will all line up . Did not find a heavy orange wire in any harness, There are 2 large pins in the plug positive and negative

 

[ryanwilson277]

Left you a message. On that diagram you sent I don't have those brown/white/green/ etc. colors on the boat side. I'm not currently at my boat right now but in the harness I have an unused thick black, a thick black, thick red, lite blue, yellow/red, purple, grey, and tan

 

[ryanwilson277]

Also a white with brown or purple stripe that doesn't go into the plug for some reason(it's faded so I wasn't sure) but I traced that to the trim guage

 

[Bt Doctur]

http://boatinfo.no/lib/library.html see manuals 3 and 17