Question about volt meter?

This is about my buddies boat. He has a fisher fishhawk ( i think) with a mercury 90hp motor. He wired up his FF on the bow ( not exactly how or with what supply) but when he got it on the water his volt meter pegged out every time he turned the key on. So he unhooked everything and he said it continues to do the very same thing.....turn key on the volt meter pegs out. Is there a reset button/switch or what other possibilites could this be.
Thanks, i know info is scratchy but thats all he could tell me.

Tom

First thing I would ask is if the TM is 24 volts and did he inadvertently wire the FF with 24 volts. I would put a volt meter on the FF wires and see what it is reading. If that is not it, sounds like the FF is faulty, at least the voltmeter part of it.
SeaRay

Are you talkin about the Voltmeter on the dash or FF?

Volt meter on dash. He unhooked the FF after the volt meter pegged out but it continues to peg out even after unhooking what wiring he did.

Its probably a bad gauge. You can double check this by checking the voltage at the gauge with a VOM (volt-ohm meter).