Ignition wiring-What did I miss?

[CheapboatKev]

68 Merc 120hp..2.5/3.0 depends on who ya ask I guess..

Had all wires off to instruments, ignition, everything.
The PO installed a secondary momentary Push To Start button...

Have her wired back up now, motor turns well..but thats all she does.
Being fairly naive, and looking at the merc manual's schematics till my head hurts.(about 3 minutes..lol)

Am I missing a wire that feeds the coil/dist? If so any idea on color and where does it go on the Ign switch? Previous IDIOT has turned the wiring on here into a plate of sphegetti..

I am getting fuel to the carb, had to install an electric fuel pump on my "barge" (as Bond-O would call her..)

She really seems like she isnt getting any spark...


Thanks in advance amigos..

CBK

 

[Don S]

Re: Ignition wiring-What did I miss?

The biggest thing that is going to cause you problems is the age of the wiring you have. The color codes are different from todays.
My suggestion would be to rewire the thing with todays wire colors and wiring diagrams.
Things have changed a lot since 68 (41 years) what do you want to do with it? Rewire or fix what you have.
That is the first choice you need to make.

PS: Merc didn't use a 140 4 cylinder (aka 3.0L) until 1969.

 

[CheapboatKev]

Re: Ignition wiring-What did I miss?

Don S thanks

I really want to get her up on the water..

I do understand the need for updated wiring harness..I dont think many of these colors have been used for years..

This year also did not (at least my motor) doesn't have the 50 amp (?)
re set button that them new fangled motors have..from 71 up?

I will search in the electronics forum and force myself to study the schematic in the manual some more.

 

[Don S]

Re: Ignition wiring-What did I miss?

You don't have to go to the electronics forum. What are you looking for.

You may not have a circuit breaker, but trhe wiring is easily updated using wire from your auto parts store. Even OEM wiring isn't tinned fancy wiring. Even if you follow your OEM colors, It just a matter of changing one wire at a time and following the wiring diagram. You could have a couple of big splices with 3 or more wires in it. Then they should be soldered. But with new wire, it's no big deal.
With all new wiring on the engine. Everything usually works a lot better. I can't count the number of boats I have done this too.

 

[CheapboatKev]

Re: Ignition wiring-What did I miss?

What I am really looking for at this moment is needing to know if there is a hot wire that goes to the ignition from the coil/dist.

Thanks for all the valuable input.

 

[Don S]

Re: Ignition wiring-What did I miss?

What I am really looking for at this moment is needing to know if there is a hot wire that goes to the ignition from the coil/dist.

Yes, there is a wire that goes from the + terminal of the coil to the ign. terminal on the ignition switch. It also include a resistor wire or ballast reisistor on the engine to cut the voltage down to prevent the points from burning up.
There is also another wire from the starter solenoid to the + terminal on the coil that puts full battery voltage to the coil for starting.

Have you downloaded manual #1 ?

 

[CheapboatKev]

Re: Ignition wiring-What did I miss?

Thank you!

I will chase that sunnof a blank down..Like I mentioned, I have her turning over..just not firing..

And yes, I DL'd all 975 pages of that manual...it is on my laptop that goes out to the garage and onto the boat. I got it before the "Adults Only" attempt to get newbies like I was to read it..
Saved my backside putting my Shifter/cables together...

I tell ya too..Silvertip has been a great help, just skimming his replies has been a big help..

 

[Don S]

Re: Ignition wiring-What did I miss?

Great you have the manual. You know your boat, so which wiring diagram (By page number) are you using?

 

[jtybt]

Re: Ignition wiring-What did I miss?

Just in case you didn't catch what Don said... The starting circuit has it's OWN ignition circuit, completely separate from the regular ignition circuit. That may be the wire you're missing.

The ign switch bypasses the 'ignition' circuit when it's on the 'start' circuit


If you have an internal resistor in the coil, run a jumper from the batt(+) to the coil(+). This is basic 'hot-wiring'.

Most juvenile delinquents in my day knew how to hot-wire a car.

 

[CheapboatKev]

Re: Ignition wiring-What did I miss?

Great you have the manual. You know your boat, so which wiring diagram (By page number) are you using?

I am looking at Section 3E-5...Figure 5.

Page 282.

 

[Gokuatsavory007]

Re: Ignition wiring-What did I miss?

Hi All I am new to this, just got me a Starcraft holiday 18. Well its a fixer uper. I was hopping that someone could tell me how to get the Manual #1 you all was talking about. Because I have no spark and have replaced all parts, still nothing!!!
So could someone pleas help me out I am going nuts here, trying to do this with nothing to go by. Thanks

 

[Don S]

Re: Ignition wiring-What did I miss?

Those manual links no longer exist.
In the future, please start a new thread about your problem and you wil probably get some help on finding why it won't start. But few will see your question at the end of some 2009 post.