No Spark in all 3 cylinders (1976 70hp evinrude)

[Josedcr]

Hi everyone,

About 3 months ago the motor running well. Then it started to feel like it was missfiring randomly at high RPMs. I checked it at he house and all sparks were long and bright. I took it out a couple of weeks later and it ran it for about 20 min, parked it and about 30 min later started it and ran it and it was sputtering constantly. It would then run great for a few seconds and then would sputter again to the point that it would almost die if I didn't throttle back. Checked it at the house and all sparks were good, but this time I could hear it sometimes miss at higher RPMs. Sat for 3 weeks...

Today it wouldn't start. Checked the spark in all 3 cylinders and found NO SPARK. Disconected the wiring harness from the ignition and jumped it straight to the starter and NO SPARK.

Before I start tearing into it, is there a usual suspect for this condition? What should I check first?

Thanks

 

[eavega]

Re: No Spark in all 3 cylinders (1976 70hp evinrude)

Suspects at this point would be stator, timer base, or power pack. CDI has a pretty easy to follow troubleshooting worksheet for checking all of these. You do need a multimeter with a DVI adapter or peak-voltage setting to correctly troubleshoot the CD ignition on these motors.

For my part, I too lost spark on all three cylinders, but it was all of a sudden. Turns out my power pack went bad. Be sure you know which component is to blame, because any one of those three components are $100+.

Rgds

 

[Josedcr]

Re: No Spark in all 3 cylinders (1976 70hp evinrude)

Thanks for the guidance. My motor is now working but it was a much simpler problem. After some testing, I noticed that the powerpack cover had been previously hit and was bowed-in and was also missing the plastic shields/spacers that are between the pack and the cover (i notice this because the motor started after removing the cover). I believe the cover was touching or too close to the stator leads on the powerpack and was grownding the power). I took the cover off, hammered it into shape and cut/installed a piece of rubber as shielding. The motor works well (still need to test it in the water)...