breaker point to electronic ignition conversion now no spark. Turns over fine.

[Steve8686]

140 mercruiser 1973. Old wiring harness on the engine was corroded in places so swapped it out for a new one and of course there are some extra wires for things that i dont have on my old engine. Shift interupter switch was never hooked up on my old engine come to find out. All I have is the wires going from a terminal block to the switch itself, no wires coming into it. new wiring harness has a green/white going from dist to what is supposed to go to my shift interupt as well as a purple wire. I plugged those wires into eachother to see if I would get spark to close the circuit but no spark. Does alternator have anything to do with spark? I have one purple wire hanging from my alternator there dosent seem to be a corresponding purple wire from my harness to go to it? i have 12 volts to coil and 12 volts to distributor? Dont make and sense. No ground wire to dist but thats what it seems like theres a bad ground.

Thanks for any help.

 

[Steve8686]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

Update, theres power coming in to the dist at the green white wire and then nothing it seems coming out of the distributor, just like the power ends at the distributor. Like maybe I put it in 180 degrees off would i get spark if it was 180 degrees off?

 

[Levinz11]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

I have a completely different engine, but I'm bored and feel like typing. On my rig I only have 12v at the coil while cranking. Supplied by the battery obviously (dont know wire color). Once the engine fires (and the key is turned back to "run") the coil is powered by a purple wire from the alternator that supplies a lower voltage 8-10 or thereabouts.

 

[Steve8686]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

Well I appriciate the input. Im pretty sure I am supposed to have 12 v at the coil even in the on position with it being electronic. I dont know. green/white wire has power going into dist. purple wire has power going into the coil with key on. This is a brand new EST system Delco Voyager.

 

[Don S]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

What wiring harness are you referring to with the green white wire in it? Did you get a new engine harness from Mercruiser?

 

[Steve8686]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

Yes, it is the new one from Mercruiser, 3.0 Mercruiser. 199 bucks from Michigan motor works.

 

[Steve8686]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

Heres a picture of it. Kinda blurry sorry.

 

[Don S]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

How about a part number or link to it, that picture sure doesn't tell me anything.

 

[Steve8686]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

MerCruiser/Quicksilver Wire Harness Assembly

 

[Don S]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

The 84-862081 A1 doesn't link to anything. What year 3.0L engine did you order it for?

 

[Don S]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

Here is a wiring diagram for a 3.0L Merc with EST, there is no green/white wire in the harness itself.
There is a green/white wire coming off the distributor and going to the shift interrupt switch.
Take careful not of what hooks to the shift interrupt switch and how it's hooked up with that distributor. You do need it before you damage your drive trying to shift without it.
On the points distributor the SI switch grounds out the igntion, with the EST it puts power to the module. DO NOT use the terminal block on the old shift plate. You need to use the quick disconnect connectors so you can put it in base timing mode to set timing.


View attachment 3wiring.pdf

 

[Steve8686]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

It is a universal harness for all 3.0 motors and that wiring diagram that you posted i have as well, the green/ white is not in the harness itself you are right. the green white is the interupter wire for the shift interuppter circuit which if I understand correctly will be the wire that temporarily kills the engine. It just goes from distributor to the shift interupt switch. The power into the shift interupter is provided by the purple wire. In the mercruiser service manual it says to bypass the shift interupter by connecting the green white and purple wires to start your base timing procedure and then hook it back up to the shift interupter when you are done. Well I cant get started when I dont have spark to begin with. I think i understand what you are saying though in that last sentance I need to put quick disconnect ends on the wires that are going to that terminal block and totally get rid of the terminal block from the shift interlock switch itself and connect them to the corresponding green/white and purple wires when i am done with the timing procedure. I understand all that now, I just dont understand why I have 12 volts to the coil and distributor and no corresponding power (spark) from distributor to the spark plugs. Its like it just dead ends at the distrubutor. I will call michigan motor works in the AM and see what they have to say.

 

[Don S]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

To see if it will start, remove the connector from the distributor that the green white wire goes to. Just take it off and move it out of the way, it's not needed until you are in the water.
Now see if you can start the engine and if you have spark. you may have to move the distributor around if you didn't get it installed at #1 TDC on the COMPRESSION STROKE.

The compression stroke is the big deal when setting timing.
HOW TO: Find #1 TDC on the compression stroke.

 

[Steve8686]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

OK, I will try that and see what i have and report back, unfortunately my boat is 60 miles away in a heated shop and wont get to it until Thursday. Appriciate the info.

 

[Steve8686]

Re: breaker point to electronic ignition conversion now no spark. Turns over fine.

Update, I put the sending wire from the tach to the bat side of the guage instead of the input side causing a direct short. Switched the wires and theres my spark. Thanks for all help.