F40BTLR rough low range RPMs

[coueytwo]

F40BTLR, motor will stutter in the low range, when I get somewhere around 2500 rpms the motor will clear and run wide open. I have cleaned the carbs in ultrasonic cleaner, then I sync/balance the carbs. I have Cleaned the carbs three times and each time the motor ran the same. On the last run I put a timing light on the motor, timing was out to 12 deg. Popped the flywheel off, broken key, ordered a new key, got it in today, installed new key, put on the timing light, the timing was right (5 deg). took the boat out, it ran great for about 10 mins, then it started to stutter at lower rpms. put on timing light, timing was all over the place.

I'm thinking CDI is failing and will test tomorrow.
pulsor coil was putting out 11v with noload.
Any Ideas?

[99yam40]

need to monitor the peak voltages into and out of the CDI before and while problem shows up to make sure they all meet specs in service manual.
Of course with the proper test equipment

[TiMn8er911]

So how did you make out, any update.

[boscoe99]

It seems that most folks that have problems think it is the CDI/ECU. Don't know why this is.

If my hand hurts because it is is red and swollen, do you think it is my brain that is causing the problem?