oil pressure guage help

[83ski2001]

i am having a problem with my oil pressure guage. it stays pinned all the way to the 80 when its on and i wanna fix that so it reads correct. i have never done any work to any guages so i have no idea where to start.

1983 ski nautique 2001
351w

any ideas?

[Nautiquehunter]

Unplug the wire from the sender and see if it drops to 0 if not then ground the wire and see if it goes to 0 . If it does replace the sender if it doesn't the gauge or wiring is at fault.