I am very new to the boating so need lots of help. I have an 83 Chris Craft Catalina 251 with a in-line 6cyl Chev 292 engine. Prop shaft runs true and prop does not appear bent or damaged in any way. (Hooked water to engine and ran engine in gear when out of water) Engine runs very smooth when reved up in neutral. 4500rpm and smooth as silk. Put into gear and vibration starts above 1300rpm. Motor will not achieve anything over 3100 when in gear. Engine mounts look very good. Boat will not plane out unless tabs are down completely and then it doesn't stay on plane once you raise the tabs. When on plane the boat still does not pick up speed. a Very slow 12mph and lots of vibration.
Where do I look for this vibration cause? Seems to me that if I'm at 12mph at 3100rpm and I could get the vibration cured, the boat would pick up some more speed and plane better once rpms were able to go around 4000.
Where do I look for this vibration cause? Seems to me that if I'm at 12mph at 3100rpm and I could get the vibration cured, the boat would pick up some more speed and plane better once rpms were able to go around 4000.