1990 yamaha cylinder 1 no spark

[bryceb]

I have a 1990 yamaha precision blend 90 hp that I just got and I recently took it out on the water for the first time.

Went great for about 10 minutes with full power. I shut it down and let it set for about 20 minutes while I fished. Started it back up and ran terribly. Couldn't get over 25% power out of it and couldn't even get it up on plane.

Hooked a timing light on it when I got it home and discovered no spark on the top cylinder.

I swapped ignition coils hoping the problem would follow the suspect coil. It did not. I swapped the ignition coil and the problem stayed at the top cylinder.

I swapped the pulser coil with a known good one. That didn't change the no spark on #1 cylinder either.

I am at a loss. Does anyone have a way to test the cdi box? What else could it be?

Any help is appreciated!

 

[robert graham]

Are you dead sure that top cylinder spark plug isn't fouled?...can't always tell just by a visual inspection....

 

[99yam40]

I would tend to believe the timing light if it shows spark on the other 2 plug wires but not on #1.
Did you see that?

I seem to remember #1 and #3 use pluser coil but #2 is generated by CDI.
I do not know what would kill just #1.

I would test the charge coil out put and the output of the CDI to all 3 coils to make sure what
was in spec and what was not

 

[bryceb]

Thank you for your responses. I'm dead certain #1 has no spark. The other two coil wires sting pretty good.

How do I test the charge coil output and output of the cdi? What specs are they supposed to be?

Again, thank you for the help

 

[99yam40]

good reading
http://issuu.com/cdielectronics/doc...t.xml&backgroundColor=000000&showFlipBtn=true