225 SW series II: No spark on #5 cyl.

[<otto>]

Max RPM at 4000. Miss at idle. The number 5 cyl stops sparking shortly after startup. Verified the coil is ok. Voltage is coming to the computer but no voltage from the computer to trigger #5 coil. Is this a known problem? Does this mean I need a new computer or could it be something else?
Help.

[<jb123>]

have you rotated coils?

[<otto>]

Yes. We rotated the coils and the problem stayed with #5. There is no voltage on one of the six leads coming out of the CDI Unit (leading to the coil). I assume this voltage triggers the coil to fire. I get a reading on the leads going into the CDI unit. Are there any sensors that could tell the CDI unit to shut down a cylinder?

[<jb123>]

sorry, beyond me there, hopefully a more experienced tech will answer you.

http://www.yamaha-motor.com/ see manuals..not sure how detailed they get,good luck !!

[<otto>]

Just an update to any of you interested. Apparently the S225TXRX (1999 225 Saltwater Series II) is designed after start-up to shut down #5 cylinder. Then at 800 RPM it also shuts down spark to #2. After 2000 RPM all cylinders spark and it runs on 6.

My problem ultimately ended up being a dead spark-plug. Not related to the #5 cylinder at all. Oh well, at least I didn't run out and buy the CDI unit.

Thanks for all everyone's help.