1978 Mercruiser 140 no spark

Wilbert 01

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Joined
Jan 26, 2012
Messages
3
I have a 140 Mercruiser in a 1978 Chris Craft Lancer. The engine cranks, has compression but no spark. I have replaced all of the ignition components and am using a remote start to turn the engine over. I have tested the coil, it is new and good.
I can't figure out where to look next.
Thanks
 

gm280

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Jun 26, 2011
Messages
14,585
Re: 1978 Mercruiser 140 no spark

I have a 140 Mercruiser in a 1978 Chris Craft Lancer. The engine cranks, has compression but no spark. I have replaced all of the ignition components and am using a remote start to turn the engine over. I have tested the coil, it is new and good.
I can't figure out where to look next.
Thanks

First of all let me say welcome to iboats. :welcome: great to have you aboard.

WOW where to start? Most engine have some sort of engine kill switch and if that switch is in the OFF position, you can crank it 'till the batteries go dead and it will never fire. So look for that switch or the wires coming from the ignition section going to the kill switch. Not knowing your setup, I can't tell you what the color of those wire could be. Some use a shorting method to kill their engine while others have to be open. But when all cylinders are not firing, it has to be something common to all of them. That would lead me to think the kill circuitry as a starting point (no pun intended)!
Hope this helps out just a little. Take some pictures of your engine setup out and post them here for everybody to help you. Also post the engine model, year and serial numbers so others can tell you the proper wire colors to look for. :)
 

Bondo

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Apr 17, 2002
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70,465
Re: 1978 Mercruiser 140 no spark

I have a 140 Mercruiser in a 1978 Chris Craft Lancer. The engine cranks, has compression but no spark. I have replaced all of the ignition components and am using a remote start to turn the engine over. I have tested the coil, it is new and good.
I can't figure out where to look next.
Thanks

Ayuh,.... Welcome Aboard,... If there's power at the (+) terminal on the coil, check the Points, which is what Fires the coil,...

There's several threads explainin' points fired ignition, up in Don'S Adults Only section, at the top of this forum,....
 

Wilbert 01

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Messages
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Re: 1978 Mercruiser 140 no spark

Thanks for the responses. I have removed every wire from the engine including the harness with the exception of the - wire from the coil to the distributor and the battery +/-. I removed the valve cover and discovered the timing was 180 degrees off. I set the timing, checked the points for proper operation tested the coil and still no spark. The plugs, wires, condenser, rotor, points, coil are new. I confirmed that I had voltage to the coil and the engine turns over. Any chance the dist. is bad? I did watch the rotor spin around with the cap off, seemed okay.
Thanks for the responses and help so far.
 

Bondo

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Staff member
Joined
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Messages
70,465
Re: 1978 Mercruiser 140 no spark

Thanks for the responses. I have removed every wire from the engine including the harness with the exception of the - wire from the coil to the distributor and the battery +/-. I removed the valve cover and discovered the timing was 180 degrees off. I set the timing, checked the points for proper operation tested the coil and still no spark. The plugs, wires, condenser, rotor, points, coil are new. I confirmed that I had voltage to the coil and the engine turns over. Any chance the dist. is bad? I did watch the rotor spin around with the cap off, seemed okay.
Thanks for the responses and help so far.

Ayuh,.... If there's voltage at the (+) terminal of the coil,....

The Points fire the coil,....

Did ya look at the links I posted for ya,..??
 

Fishermark

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Joined
Oct 19, 2003
Messages
5,617
Re: 1978 Mercruiser 140 no spark

A couple of notes come to mind - how are you checking for spark? Many of the things you mention, while important, do not affect whether you have spark. The timing being 180 degrees off for one. As Bondo mentions, the points fire the coil by momentarily grounding out the coil. Let us know how you are checking for spark. (You did not put the wire from the neg side of the coil to a ground I assume? That will keep the coil from firing as well).
 

thumpar

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Joined
Jun 21, 2007
Messages
6,138
Re: 1978 Mercruiser 140 no spark

Thanks for the responses. I have removed every wire from the engine including the harness with the exception of the - wire from the coil to the distributor and the battery +/-. I removed the valve cover and discovered the timing was 180 degrees off. I set the timing, checked the points for proper operation tested the coil and still no spark. The plugs, wires, condenser, rotor, points, coil are new. I confirmed that I had voltage to the coil and the engine turns over. Any chance the dist. is bad? I did watch the rotor spin around with the cap off, seemed okay.
Thanks for the responses and help so far.
Did you put the - to the battery? It is not supposed to be. Also is the tach still hooked up. A bad tach can cause problems.
 

Bt Doctur

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Joined
Aug 29, 2004
Messages
19,093
Re: 1978 Mercruiser 140 no spark

How much do you know about the engine? Assuming it was running at some point prior to your post then it would not just jump time, Was the dist removed for any reason? How did you test the coil? Do you know how to install, clean, or test the points?
 

MikDee

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Joined
Jun 6, 2007
Messages
4,745
Re: 1978 Mercruiser 140 no spark

Thanks for the responses. I have removed every wire from the engine including the harness with the exception of the - wire from the coil to the distributor and the battery +/-. I removed the valve cover and discovered the timing was 180 degrees off. I set the timing, checked the points for proper operation tested the coil and still no spark. The plugs, wires, condenser, rotor, points, coil are new. I confirmed that I had voltage to the coil and the engine turns over. Any chance the dist. is bad? I did watch the rotor spin around with the cap off, seemed okay.
Thanks for the responses and help so far.

How did you reset the timing? Did you pull the Distributor out, & give the rotor 1/2 a turn?
 

Wilbert 01

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Joined
Jan 26, 2012
Messages
3
Re: 1978 Mercruiser 140 no spark

Gentlemen, thanks for all of the help. After reading the posts and following the link to the adult section, I pulled the cap and after checking the points again, figured I would clean them with some sand paper just for the heck of it. They were installed new in January 2014. I then bumped the engine over and had strong spark. I put the cap back on and the engine fired right up. Thanks for all the help. Now on to removing and draining the gas tank and confirming the engine will cool.
 
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