I have completely repaired my Mercruiser 3.0 140 engine and drive unit. Everything is ok except for one thing. When I take a curve or turn at WOT I lose RPM, even after I straighten back up and get going good it loses from about 4800 down to about 4100 and stays that way until I throttle back down and start over, then it goes back up to 4800. Have no clue if this is serious but it does not seem right. Any ideas?