Welcome to SCJB.
Is it possible it may have been old water that was up in the hull? Sometimes water makes it's way up under the floor and it came out
when you were backing down the ramp.
Assuming everything is sealed and there are no cracks/holes in the hull, look where the water comes into the boat: the drain plug and inlet pipe from the jet for the motor cooling.
Was the plug in? Is it in good shape? Sometimes simple stuff is easily overlooked.
Are all the cooling lines and fittings tight and in good shape?
Take a look around the jet, inside and out, and look for any blown out gasket or silicone. Any loose nuts around the intake or bowl?
Are the packing rings loose or worn? These are rope seals that seal the opening where the shaft comes out of the suction housing.
They may need to be tightened or replaced.
Good luck.
Your bilge pump works, right?
