I have a 2003 Sportster 4Tec 155 hp.wake edt. Installed new Solas 11/19 with new wear ring , runs 51-52 (GPS) with a wake tower. and no more cavitation out of the hole. BIG improvement over stock prop...... Good Luck
I have the same boat ( 2003 ) 4tec. I replaced my oil pressure switch last year. I had the same problem. I would not replace the solenoid just yet. It sounds like its working fine. I think your problem is old gas. Keep in mind this new gas with ethanol has very little shelf life. Its creating a lot of problems in boats and everything else. Are you sure you did'nt damage your prop or wear ring with the rock ?