I replaced the fuel sender, installed pp which meant I taped into that tach wire, replaced the battery and added another with a battery switch, and just cleaned most of the electrical connections so it could have been a few things! This link might help with your gauges! It helped me with a few issues.
Haha I would love to run the hours up on this boat! Unfortunately I got a new a22 and I dont think buyers will believe this thing only has 7 hours!