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No provision for oil temp on that model.
Smartcraft data (especially RPM's) is "dead-on accurate".
Get someone to help you check to make sure you are actually reaching WOT at the engine. I've seen several 150's that were NOT.
Then work on your setup... What "21" are you running? That boat can be made to run quite well without a jackplate, if engine is at correct height, correct prop choice, etc.