1978 evinrude 70 horse engine surging

[ing]

I have a 1978 70 horse evinrude. just rebuilt the carbs and the motor runs much better than before but still acts as if it is occasionally running on 2 of the 3 cylinders. it seems to run good for a bit and then acts like it is bouncing between 2 and 3 cylinders. any ideas on what to check next would be greatly appreciated.

 

[jonesg]

Re: 1978 evinrude 70 horse engine surging

Warm it up and do a spark test, go to autozone and get a GAP tester.
All plugs out, set gap to 3/8th inch, should jump gap with blue spark, not yellow spark. Have someone crank the key or jump the starter yourself.

I suspect its dropping a coil, check coils if it fails spark test, look for tiny cracks. I would replace them all if old.