Originally posted by rsr:
Running a jacuzzi 12wj. Recently had it rebuilt and blueprinted. Was running a 455 prior to the blueprint. Just put in a fresh 454. First time pump ran since blueprint was with 454. Noticed a loud growling noise when had it in reverse. Noise kind of comes and goes. Can slightly feel this in the boat. Did not notice this noise or vibration while in neutral or forward. Any ideas what this might be from? Pump overpacked with grease (Did notice some expected grease loss during intial runs) or possibly the impeller out of balance. Any and all help would be much appreciated.
I had a strange noise coming from my boat once, only at around 3500 - 4000 rpm and turning left. It turned out to be a siezing U-joint in the driveshaft. Did you have the u-joints changed when you had the motor and pump done? Also, a steel impeller can create a rattling noise at idle that a aluminum will not make. In reverse, you may be causing a slight cavitation condition in your pump that could be causing the noise.
JB