erratic tach on 88 johnson 150

[Scotty B]

I I have a 88 stlcca150
I have noticed the last couple times out that, the needle on my tach will bounce as I am making a run. The motor don't seem to take any effect from it.
is this telling me I am going to need a stator??
any ideas would be great thanks

[baker1]

You'd need a peak reading meter to read the stator output but I'd focus on the wiring connections from the rectifier, clean the main harness cannon plug prongs too and check the connections at the back of the tach, signal is the tan wire from tach to rectifier.