need help with switch box

[jamesg1972]

this is the first time for me posting, hope this is right. i've look under switches couldn't find my answer. i have a 1986 mercury 150 xr2 motor. i have one side of the motor will spark all three plugs, the other side none of the plugs will spark, is this the switch box. is there anything i can test before i go and buy a switch.

 

[86RajunCajun]

Re: need help with switch box

Switch the no spark side switch box out with the good spark box and see if the problem follows the bad box. If so, replace it.

 

[CharlieB]

Re: need help with switch box

Disconnect the white 'Bias" wire between the two boxes and test for spark again.

DO NOT TRY TO START THE MOTOR

A bad bias circuit on the box that sparks may be blocking the other box from working.

If you now get spark on all cyl's the replace the original working box. Mark this box as '3 cyl ONLY' it is still good for a 3 cyl motor.

If still no spark on one side then switch the boxes

If spark switches sides the box is bad, if spark remains on the first side then the stator is bad.

 

[jamesg1972]

Re: need help with switch box

thanks for the help. i removed the white wire nothing change. then i switched the boxes, and the other side sparked.i will replace the box.