Mercury 25hp 2 Stroke one spark only

rib-x450 · 17 October 2008, 16:47

Does any one know:

I have a 25hp 1988 2 stroke, the engine only sparks on one cylinder?

I have changed the plug and coil , one has a good fat spark one has nothing?

Is the switvh box a possible fault, or would both not plugs not spark.

Has anyone got a switch box for this engine, I can buy or borrow to try it?

Any help greatly appreciated.

Locozodiac · 17 October 2008, 22:14

Could you post pics of both engine sides to see CD unit and plug coils and to look for a compatible engine type ?

Downhilldai · 17 October 2008, 22:55

Is the HT lead ok?

rib-x450 · 18 October 2008, 13:30

I have checked the earth of both coils, is there on sensor per coil or two from the flywheel?

I would have thought CDI would work or not ........... can believ one side is ok one isnt?

Any more thoughts?

ian parkes · 18 October 2008, 13:38

Take the coil lead and plug from the side that is working OK and fit it the other side , that will at least rule out the chance of a second faulty coil lead or plug.