That may not be unreasonable pressure to see on the oil press gauge. The instrumentation in the boat is not necessarily calibrated to exact figures(such as you would expect to see if the gauges were digital vice analog).
If your oil pressure were in fact 80 PSI that would be cause for concern. At 70 PSI indicated you may be within gauge error of the normal range depending on the quality and accuracy of the instrument.
Make sure you have the engine up to operating temp and stable prior to WOT operations. If the oil is thick it will impact the gauge reading on the high side.
The bottom line is follow the recommended specs set by the manufacturer and if you feel that the gauge is innaccurate or reading excessive get it checked out by a qualified tech.
If you suspect that the oil pressure is higher than normal then I would recommend changing the oil filter as a first step. If the oil pressure is senses ahead of the filter then a clogged filter would register high on the qauge while providing low pressure to the bearings.
Check the power, signal, and ground connections to the back of the gauge. A weak power or ground connection will cause the gauge to read high. I ended up building a new wiring harness for my dash. None of the gauges were reading correctly.
Linear Mode
