Merc 90 Tach pegs past 4,000

[Justinp15]

I have a 2002 cress pontoon with 90 merc outboard, faria gauges, and the tach works fine till WOT then when it passes 4,000 it pegs out to max. I think it’s doing around 5,000 but gauge reads max. Any thoughts on why max out after a certain point? Thanks

 

[HotTommy]

Welcome to the forum. As this question is more about the engine than the boat it sits on, I suggest you post your question on the iboats Mercury engine forum. You may get quicker answers.