DT115 no rpms over 3000

[olyball]

1989 DT115 has 295 hours on it. Have been struggling with several problems over the last few years. Thought I had it all figured out until yesterday. Running great but then at near full throttle, the boat came off plane and the rpms dropped to about 3000. Have had this happen before, but always with an alarm, was low oil. This time, no alarm. Oil is full, water is good.

I am hoping it is not the CDI unit. Is there a list of things to check before spending the $900 for a new CDI?

[mitch]

Still sounds like a alarm check that buzzer is not broken