1986 90hp inline 6, spark problem

Hi,

I have a strange spark problem...1 and 4 have no spark at idle but kick in around 2500 rpm, but look weak, kinda blue/orange color. stator new, trigger ohm'd out ok, new plugs, new rectifier. Power packs run 1,2,3 and 4,5,6. Seems strange that they could both be bad. Any ideas or suggestions?

Thanks,
Don

Re: 1986 90hp inline 6, spark problem

i have been having a similar problem with my 1985 inline 6. i have replaced everything you have and still nothing. another thing that could cause the motor to loose spark is the switch box. i am going to pick one up tomorrow and ill be in touch with the results!
-Ryan

Re: 1986 90hp inline 6, spark problem

check all the wires and connections on your switch boxes. one of mine were bad. and that solved the problem. i also had a bad wire in the wiring harness. check ALL connections! i cant stress that enough. because this can be from MANY problems.

-Ryan

Re: 1986 90hp inline 6, spark problem

The common part with cyl's 1 & 4 is the trigger.

There is only 3 triggers, each triggering both switchboxes alternately.

If you test the 1/4 trigger with a DVA meter you may find it failing in the idle position then begin working as the throttle/timing is advanced, indicating a broken wire in the trigger harness where is moves.

Testing with an Ohm's meter can be deceiving as a broken wire butted together may still give an Ohms reading within spec yet fail to carry sufficient current once the sytem is operating. The DVA meter will place enough load to prove any fault. Disconnect the throttle cable and advance the timing while cranking/testing to watch for any change in the DVA reading.

Re: 1986 90hp inline 6, spark problem

check your mercury switch..