Mercruiser sterndrive No Spark

[billywazz]

I have a 1987 Mercruiser sterndrive with a 120/2.5L GM 153 I/L4 . I replaced coil, condenser, rotor, cap, wires, in attempt of tune up.
It ran good all day. Got stuck in thunderstorm that night and took on some water.
Next day it ran rough. Like fouled fuel.
Next day would not start at all.
Looked for spark by pulling plug wire and holding near block, No Spark.
Got 12volts at coil when key is on.
A mechanic told me to look for a rectifier diode. I dont see one on wiring diagram. I do have a resistance wire to electric choke but I didn't do anything with it.
Any suggestions on next step

 

[Bondo]

Re: Mercruiser sterndrive No Spark

I have a 1987 Mercruiser sterndrive with a 120/2.5L GM 153 I/L4 . I replaced coil, condenser, rotor, cap, wires, in attempt of tune up.
It ran good all day. Got stuck in thunderstorm that night and took on some water.
Next day it ran rough. Like fouled fuel.
Next day would not start at all.
Looked for spark by pulling plug wire and holding near block, No Spark.
Got 12volts at coil when key is on.
A mechanic told me to look for a rectifier diode. I dont see one on wiring diagram. I do have a resistance wire to electric choke but I didn't do anything with it.
Any suggestions on next stepView attachment 151864

Ayuh,.... If it's got Points,.... Change 'em...

 

[89sandman]

Re: Mercruiser sterndrive No Spark

crank the engine and see if the volts to the coil "strobes" this means goes up and down, if volts remain constant that means your points aren't working.

 

[billywazz]

Re: Mercruiser sterndrive No Spark

Took it to a mechanic last week and he told me I was only getting 6 volts at coil, but he did not fix or tell me why. It seems he doesn't have the time for me. Knowing I'm only getting 6 volts at coil where should I dirrect attention. All wires, from battery to starter. from starter to coil. from coil to choke and points all look good. Maybe starter solenoid has a short?(but engine turns over fine). Any advice would be helpful, thanks.

 

[Bondo]

Re: Mercruiser sterndrive No Spark

Took it to a mechanic last week and he told me I was only getting 6 volts at coil, but he did not fix or tell me why. It seems he doesn't have the time for me. Knowing I'm only getting 6 volts at coil where should I dirrect attention. All wires, from battery to starter. from starter to coil. from coil to choke and points all look good. Maybe starter solenoid has a short?(but engine turns over fine). Any advice would be helpful, thanks.

Ayuh,... Have ya changed the Points yet,..??

 

[Eric 3.7LX Alpha 1]

Re: Mercruiser sterndrive No Spark

The coil will only get 12v from the purple/yellow wire on (+) terminal when the starter is cranking the engine. When you release the key and switch is in "run Position" coil will get power thru the purple resistance wire (which lowers the volts down some) on the (+) terminal to extend the life of the points, which should have been changed with your tune up.

 

[Oshkosh1]

Re: Mercruiser sterndrive No Spark

I replaced coil, condenser, rotor, cap, wires, in attempt of tune up.
[/ATTACH]

...cue the "points" suggestion(again) and ensure you set the dwell correctly, along with new plugs you'll also buy and gap. Can't have a "tune-up" without them.

Pull the plugs, read'em...see what they tell you.

 

[billywazz]

Re: Mercruiser sterndrive No Spark

I did change the points and set the gap it was partr of tune up kit. I also did spark plugs,wires, cap, electiric choke, coil, rotor.

 

[achris]

Re: Mercruiser sterndrive No Spark

Have a read of this thread. It explains how the points system works, why you need a resistor (or resistive wire) and when you do and don't get 12 volts to the coil...

http://forums.iboats.com/showthread.php?t=329742&p=2186518#post2186518

Did you change the condenser? Lightning would have zapped that puppy right off the planet!!!

Chris.......

 

[bonniesouth]

Re: Mercruiser sterndrive No Spark

Have a read of this thread. It explains how the points system works, why you need a resistor (or resistive wire) and when you do and don't get 12 volts to the coil...

http://forums.iboats.com/showthread.php?t=329742&p=2186518#post2186518

Did you change the condenser? Lightning would have zapped that puppy right off the planet!!!

Chris.......

Did you get it fixed? If so, how did you do it. This is the same issue I am having and I am out of ideas. 1983 omc 2.5l
New starter, new coil, right amps going to coil, no spark from the coil, rotor turns and open and closes, points look beautiful, baffled. maybe a ground issue? Followed the diagnostics through the troubleshooter. Just no spark coming from the coil? Uggghhhh Turns over but no spark. Seems I have narrowed it down to the coil, then replaced it. Must be a ground issue or something. I read that there is some kind of connection with the coil and the tach?

 

[Don S]

Re: Mercruiser sterndrive No Spark

Welcome to iboats bonniesouth, You need to start a thread of your own. You may have the same type problem but your problem could be something else. You also need to post in the OMC forum, this one is for Mercruisers.