2 cylinder I Unplug Spark Wire and Motor Dies .

[kjack333]

I have a 2 cylinder , 4 stroke . I unplug top spark wire and it just looses a little power . If I unplug the bottom spark wire it dies . I added new spark plugs a couple weeks ago . 2000 Nissan NSF15B . I just bought the boat and have never had the motor in water . The previous owner siad he thought it was running on one cylinder . What could my problem be and options . Thanks for any help .

 

[gm280]

Sounds like the upper spark plug coil is going out but firing erratically now. I'd swap the coils and see if the problem follows the upper coil. If it does, I'd replace the coil. If it doesn't follow the coil, look at whatever is feeding the coils... JMHO!

 

[Sea Rider]

If it's a siamese coil pack must change entire coil assy.

Happy Boating