1979 Seahorse 85hp. Runs very rough at idle (sputters) and wot is very low rpms and sounds like running on one cylinder. Checked compression and all 115 -120. Cleaned carbs and put in kits. New plugs getting wet. Bought a spark gap tester and was getting marginal spark on starboard side and lightning bolts jumping great distance on port side. All coils measure same ohms. Swapped power packs and now port side has marginal spark and starboard has nothing. Swapped packs back and marginal on starboard again and now very weak on port. Scratching my head. ??? I'm not sure what could be causing spark to be intermittent?