Outboard Rigging

[rcnight]

I just repowered my 83 CC with a 97 Evinrude 150. The engine came with the wiring harness & ignition switch. Missing was the System Check gauge - so I bought an OMC tach with the system check incorprated. Naturally the connectors and the wire colors don't match, althought the number of wires do match. Also, since the new system only offers a temperature warning, is a temp gauge needed? I thought I'd replace the temp gauge with a water pressure. All replies appreciated.