115 hp 2 stroke not firing on port cylinders

[jetskijersey]

When returning to service after winter layup, the motor only has ignition spark on the starboard 2 cylinders, no spark on the port side.. The motor is a 1995 with the cdi mounted on the rear exhaust plate, and the smaller coils mounted on the outside of the cdi box.
Has anyone experienced this before, and what was the cause, please?

 

[hosteter]

If there is no spak i assume that a ignition coil broke down.try to change the cables between coils and check the sparks.then you will se which ignition coil works and which not.

 

[hosteter]

What abbout cables and spark plugs?

 

[jetskijersey]

I have changed the cables between the coils and proved that the coils, ht leads and spark plugs are all good. Thanks for your response!

 

[hosteter]

Dont understand.if the coils,cables and spark plugs are all good why there is no spark

 

[99yam40]

need to test all the inputs and out puts of CDI with the proper test equipment to compare to specs in service manual

 

[jetskijersey]

Thanks for your suggestions everyone!
Happily I managed to get hold of similar components, so that I could measure resistances between wires of the different components and compare them to my motor.
As a result I found a poor/intermittent connection on 1 wire in the the 4 wire connection block from the advance/retard trigger/pulser assembly. I replaced it with a new waterproof connector, and now we have full ignition on all 4 cylinders! Motor is running smoothly.
I have never experienced this fault before, so was a bit confused !
Once again, thanks for your help!