Don Bowers of Dons pump service in Ohio always claimed to have invented the Marine Jet drive "inducer" ,held a legitimate US patent on it and defended/fought for it till his untimley demise (RIP) . I'm not sure I want to enter the "fray" of who actually had the Idea but internet research shows "pre impellers" in multiple applications (rocket fuel pumps and on and on) have been around along time . I actually have done rather exausting research into this and have my own opinions as to who came up with the idea . But for now I'll say they work very well in some instances and not much help in others. We've used and installed them with huge sucess and positive feedback, I'd definately consider one in my boat but in your case john I'm not sure the "bang for the buck' is there Heres what my esteemed pump parts supplier says Tom
INDUCER IMPELLER
PART # IM1000
The Inducer impeller is a revolutionary new concept that feeds water to the jet. Because the Inducer is not shrouded it can flow 20% more water to the impeller than the impeller can use. This helps keep the impeller loaded and absorbing all the power the engine can produce.
Problem: Pulling skiers with small impellers (B or C) and high performance engines. The small impeller does not work well for the hole shot but is designed to let the motor turn more RPM at top end to reach desired speeds. This makes pulling skiers near impossible.
Solution: The inducer impeller is designed to feed enough water to the impeller to keep it hooked up. Resulting in tremendous hole shot and the ability to pull skiers. This does not affect the top end speed.
Problem: Heavy white water. In turbulent white water the jet takes a gulp of air causing the impeller to spinout while negotiating a large rapid. In some cases the jet can take too long too recover resulting in a potentially dangerous situation.
Solution: The inducer feeds water to the impeller almost instantaneously. Resulting in no toss of forward progress.
Problem: Large heavy boats with a radical engine. The large boat dictates that the impeller should also be large. By using a large impeller hole shot is increased but the motor cannot turn the appropriate RPM to reach desired top speed.
Solution: By using a smaller impeller along with the inducer a person can have the best of both worlds and not sacrifice hole shot or top end.