not firing

[wojack]

1990 mercury 40hp classic out board 2 storke 4 cyl.the motor is only firing on the bottom two cylinders can pull plug wires off when running and on the top two cylinders has no spark. Moved coils from top to bottom and they worked.I dont know how to check electrical if stator is working or the switch box .Does any one know this problum I heard usually its the switch box but it coust too much to guess??

[Wgoodrich]

check backwards from your coils. Should go to the electronic ignition. Check to see if power impulse is entering those two dead coils. Then if it is not getting the impulse into those two coils check the impulse into the electronic ignition. Is the power impulse is entering your electronic ignition but not leaving to those two coils then you have lost your electronic ignition. If you have no impulse entering your coil to fire those two coils then suspect the parts before the electronic igintion.

Hope this helps some

Wg