WHY DOES MY BOAT PORPOISE? BOW BOUNCES?

I just bought a 2005 carolina skiff sea chaser flats boat.. It is 20' in length and has a 2005 yamaha 150 4 stroke.. The boat has a hydraulic jack plate.. boat gets up good and plains out.. My problem is even with plate all the way down and trim all the way down the bow still porpoises.. Well, as you can imagine, you get poor performance because the motor is all the way down on jack plate and trim.. if you go up with either you get worse bounce..



the only thing i can think is causing problems is the prop.. It has a old aluminum prop and i don't know the pitch but the blades are very wide.. I am not a prop guy so i am guessing he prolly had a nice stainless that he swapped out before selling.. Could all my problems be in the prop???WHY DOES MY BOAT PORPOISE? BOW BOUNCES?
Changing the prop don't believe will fix your problem. porpoising generally is caused by too much weight in the rear, 90 degree flat transom on a flat bottom boat, or the boat has a hook in the bottom near the back. putting transom wedges between the engine and the boat sometimes takes care of this, or a wale tail with a down curved fin. you can check the bottom of the boat with a Straight edge for the hook.WHY DOES MY BOAT PORPOISE? BOW BOUNCES?
Actually when the jack plate is all the way down, it should get worse. Different things cause porpoising. Motor too low, to much weight in back, no negative trim, and also wrong prop. SS props hold on to the water better then aluminum because they don't flex as much. Could be a big part of your problem.WHY DOES MY BOAT PORPOISE? BOW BOUNCES?
Put some weight in the bow. It sounds like you have all the weight in the stern.