You need to pull up the floor board section to which the motorbox is mounted (at the hinges), and put some sort of reinforcing material beneath the screw attachment points. That honeycomb aluminum stuff was no match for the force of the screws and tiny washers used from the factory. I used a small strip of treated plywood and some large washers and it worked great. You may need some longer screws.
If I recall correctly, your boat has two removable floor pieces, and the hinges are attached to a very small piece. You might just want to replace the entire piece with something more durable and waterproof.
Previous: 1993 Prostar 205
Red 1998 Ski Nautique, PCM GT40, 310 hp, , Acme 4 blade, Perfect Pass SG/Zbox.
Be kind. Have fun.