We don't see many , well hell ANY Buick powered boats around here, Welcome! Can't wait to see it!
First, you need to post pics of the boat. Particularly of the engine compartment, to see how your set up is.
Second, if at ALL possible, disconnect the driveline from the jet. Not usually possible with 3 point mounts. In which case, what I do, and don't really endorse, is run a second hose like an enema up it's ass. at least it's SOME water to the jet, but don't run it too long or hard like that.
Heres a pic of my setup on Moo. My Pickle is setup similar, but with all AN fittings is all. pull a cap off, hook up the hose (With a valve to control the water). With Moo, I loosely clamp vise grips around the red hose from the pump to feed it just a little, then a hose up the wazoo WFO as disconnecting the driveline is impossible on that one. The pickle is a 4pt mount, and 5 minutes to disconnect it.

Ray