Erratic tach reading at high speed

[javelin225H.O.]

This morning I noticed my tach was bouncing back and at wot. The last few outings the voltage gage was bouncing too, sometimes showing 16 volts. I would hit the trim switch and it would drop it down to normal voltage. Well then the tach really started to jump at wot, down to 2000 then up and down. Fuel gauge goes out, voltage gauge goes out, wouldn't start, had no power to the motor. Trim wouldn't work. Finally it cranked up. At idle everything was fine until about 3000 rpms then it happens again. All gauges bouncing. All the check engine, oil, heat no oil alarms would cycle on when running. It would cycle then a few minutes later cycle again. I notice it started when I used the trim switch on the throttle.
What could cause this? Power pack, strator? Short in the trim switch on the throttle?
This is for a 1999 Johnson 225 H.O.

Thanks for your help
Michael

[sandbar]

Check under cowling and make sure all connections are tight no wing nuts on battery & look under powerpack & make sure rectifer isnt starting to short....

[javelin225H.O.]

ttt