1986 Mercury 90 hp 6 cylinder only running on #2, 4 and 6 cylinders

[Gunner54]

Only has spark in the even numbered cylinders. Any ideas what to look for?

New plugs, new fuel.

Any thoughts where to start?

 

[racerone]

Sounds like a bad switch box.-----There are of them.----You could test by swapping them and see if there is no spark on 1 , 3 and 5 and spark on 2 , 4 and 6.

 

[Faztbullet]

Also could be stator

 

[Gunner54]

Thanks for these suggestions.
Sorry, I'm new to this, can you point me to the locations of both switch boxes and stator.
Makes sense switching switch box to determine if this is the issue.
Is there a test for stators?

 

[Chris1956]

The CDI electronics web site should have a troubleshooting guide for the ign system.

Your motor will have twin switchboxes. Trace wires from under the flywheel to the switchboxes. They may be stacked.

There is usually an ohm test for the stator windings.

 

[Faztbullet]

Just exchange the red/blue wires to opposite switchbox's. If 2,4,6 starts firing and 1,3,5 stops its the stator. If problem stays replace BOTH switchboxes with omly OEM, Serria,EMP or CDI/Rapair

 

[Gunner54]

Just exchange the red/blue wires to opposite switchbox's. If 2,4,6 starts firing and 1,3,5 stops its the stator. If problem stays replace BOTH switchboxes with omly OEM, Serria,EMP or CDI/Rapair

It's firing on cylinders # 2,4 and 6 now.
If changing the wires and it still fires on 2, 4 & 6 I'm unclear as to why this points to the stator as faulty?

 

[Faztbullet]

Is 1,3,5 sparking?

 

[Gunner54]

Is 1,3,5 sparking?

LOL, I thought my thread title was clear, cylinders 2,4 & 6 are running (firing).

 

[Faztbullet]

If even cylinders are still firing after wiring swap replace switchboxes as a pair

 

[Gunner54]

If even cylinders are still firing after wiring swap replace switchboxes as a pair

Ok thanks will check it, sorry for any confusion.