1987 Mercruiser 3.0 No Spark

[jshark]

I am restoring a 1987 Four Winns Horizon 170 and have no spark. I replaced the coil.

 

[achris]

Need a bit more than '1987'. What is the engine? Title says 3 litre, but you say '170'. 3litre was 130 or 140hp. The 170hp was a 3.7litre. Please post your engine serial number, and what ignition system you have (points, DDIS, EST)...

Chris.....

 

[jshark]

My apologies sir. The 170 is the designation for a 17” boat. It’s an in-line 3.0 130HP with points.
The engine serial number is B515180.
Thanks in advance!

 

[jshark]

Have 12 volts, both sides of the new coil and at the points. Could it just be a bad condenser?

 

[Bondo]

Have 12 volts, both sides of the new coil and at the points. Could it just be a bad condenser?

Ayuh,...... Welcome Aboard,........ ya need voltage at the movin' side of the points, 'n ground at the mounted side, 'n the points should be sanded, or replace,.....

 

[jshark]

Are there and other functions of this system that would kill the spark outside of the coil, distributor, etc? I’ve read some posts about the tach not working?

 

[Bondo]

Are there and other functions of this system that would kill the spark outside of the coil, distributor, etc? I’ve read some posts about the tach not working?

Ayuh,..... So disconnect the tach wire at the coil to test that theory,....

 

[achris]

With the points closed, measure the voltage on both sides of the coil. Should be 0v on the coil negative and about 8v on coil positive...

What do you have?

Chris....

 

[jshark]

Chris... battery connected or disconnected? Key on or off?

 

[jshark]

Measuring with the key on I have 12.6v on both sides.

 

[achris]

The points aren't closing electrically. Take them out and clean the contact faces...

Chris....

 

[jshark]

Chris,

I did as you suggested. I figured I may as well just replace it all? When I pulled the points they were completely burned through on the on side. Replaced points & condenser, cap, rotor, wires. Have great spark!!

Thank you for your help sir!!!

 

[jshark]

And I had 7v on the positive side and .4 on the negative. Could just be my tester?

 

[achris]

And I had 7v on the positive side and .4 on the negative. Could just be my tester?

Sounds perfect!