yamaha 650 waverunner , weak spark wont fire?

i would try a new battey and of that doesnt help then the best thing to do is disconnect the ignition switch and any kill switches and try and short the two main starter relay wires out and see if the spark is any better then,if not then the only thing left is the primary ignition coil in the generators stator coils this is very common on motorcycles and jetskis alike.

adam bike doctor
July 2010