1989 yamaha 115 CDI/ignition problems

[willametteriveroutlaw]

I have a 1989 yamaha 115 that I just recently replaced the CDI on, the origional CDI had no spark on 1 and intermittent spark on three. I had my mechanic run a bunch of tests to confirm the CDI was faulty. I ordered a new CDI and had it installed last week. I water tested my boat and it ran fine. On the next trip, the my boat began running rough and after another series of tests, there is no signal coming out of the cylinder 1 output on the CDI. The input tested fine.

Did I get a defective CDI or could there be another problem causing the CDI to fail?

[boats.net]

Getting a defective CDI would be extremly rare, double check charge coil output to CDI unit.

[willametteriveroutlaw]

I'm showing power on the input side when I test it. Is there a specific test I can do to test the charge coil output to the CDI?

[99yam40]

what kind of power are you showing?
Are the charge coil voltages meeting the minimum specs in the manual?
What about the pulsar coils?
What kind of meter have you been using to do the testing?

There are capacitors in the CDI that store the voltage from charge coils, and the pulsar coils tell when to send it to the plug coils.
I have read that if a open happens in the out puts it can cause high voltage feed back and hurt CDI, but do not know that for positive

[willametteriveroutlaw]

I am not sure, my Mechanic is doing them for me to be honest. He was just unsure of what could kill the CDI.

[99yam40]

Transformers, capacitors, and other electrical devices can be harmed if their voltage rating is exceeded.
This can be done by voltage spikes due to bad ignition coils, bad wiring to the coils, or some one pulling the plug wire while running to see if that makes a difference from what I understand.
Any one of these things does not give the voltage stored in the cap anywhere to jump to when it tries to fire or interrupts the discharge and ends up with a back feed spike kind of thing. I never really understood it that well but have heard electrical engineers discuss it at length on some large transformers we had fail. They said it had to do with the speed at which the 15KV breakers opened or maybe it was close, causing a ripple effect that sent a voltage spike that jumped in the windings and things went boom

[willametteriveroutlaw]

So I bought a new stator and have a replacement CDI coming.. Any other parts I should replace while the bleeding is happening?

Salmon season is coming and I do not want to miss a day..

[99yam40]

hard to say without the testing results for all parts