Hi, Im new to jet boats. I bought a beat up 1978 glastron carlson cv-23. It has a ford 460 and a Berkly 12JE.
The boat also has hydraulic trim tabs. I finally got the thing into the water to do a wet test. It idled great through the marina and steered well. But when given gas at higher rpms it was very slow to get up to plane. I could hear it was cavitating bad, but eventually planed out. However when we made a turn at speed it slowed down to a crawl and the engine rpms started to rise. Before I could back down on the throttle, the temperature spiked at like 280 degrees and the engine quit.  Well long story short...we had a nice afternoon of floating til the wind pushed us against the rocky beach....and eventually towed to the marina.
I crated up the jet and sent it in to berkly for a rebuild. 
    Question= If the trim tabs were all the way down could that have caused the jet to cavitate to the point where no water was going to tne engine ?
     And I would like to install a jetovator, How would the trim tabs affect the performance?