View Full Version : need help on prop/prop shaft

07-29-2008, 12:26 AM
Okay, so I've been boating for 30+ years and the odds are eventually I was going to hit something. Was pulling a wakboarder in 16ft of water and heard/felt a huge thump. shut the boat down and went back to pick up the boarder. discovered a 6 inch diameter log floating 6 inches under the water about 12 ft long :mad:. After this boat was running loudly and rough and pulling to the right ( I have a 2006 X1). Found that there was vibration and loss of power so knew it had to be prop shaft or prop. From the attached pictures even the mechanically challenged like myself can tell that ideally the center of the prop and shaft will line up with the rudder. The second picture is the brace for the prop shaft. Does anyone know how to tell if the brace is bent or the shaft itself? I live 100 miles from the dealer and would like to have them have the parts before I get there.

Funny how trusting God changes your perspective. At first I was really upset but then I realized, it's only by the grace of God someone wasn't hurt and that I'm able to afford the repairs. I actually was able to be thankful for all the time's I didn't hit something when I wasn't paying attention. It's not going to be cheaper knowing I was watching and still hit it but it is easier to live with. All you can do is all you can do.

07-29-2008, 12:35 AM
Actually, everything looks pretty good. It is normal for the rudder to be offset from the propshaft; it allows removing the propshaft without pulling the rudder, and may help offset pull related to the rotation of the prop.

I'd take a close look at the prop and see if the blades are bent; maybe rotate it by hand and see if there's an obvious wobble. That's the most likely bent component. You could have your dealer inspect the shaft/strut to see if they're bent.


07-29-2008, 12:42 AM
I looked at the prop and thought there was some angle change but wasn't sure. There is nowhere on the bottom of the hull or the tracking fins with any evidence of impact. The boat was running about 15mph at 2500 rpm which is about 5 mph slower than normal. I really thought there would have to be an obvious bend in the prop to change ouput that much.

07-29-2008, 06:31 AM
The prop looks to bent.

07-29-2008, 07:30 AM
You could try laying a straightedge along the shaft, but I suspect that only a runout gauge will tell for sure. As to the rudder, that is normally offset from the prop shaft, so your picture looks ok.

Unforunately, it's going to take a thorough inspection by someone with the right tools to check the alignment and condition of the shaft/strut combo. The prop - I'd just send that right off to OJ and get it rebuilt. You probably should consider buying a spare prop while you're working with them.

07-29-2008, 07:41 AM
Definitely a bent prop. I agree with bigmac. You drove it for a period of time to get back in. If there was a bent shaft you would start to see it in the bearing material that the shaft rides in through the support strut and ultimately you would start to see a packing leak. Hey Over 35 years of boating and two years ago was the first time a hit a submerged object. Mine was more obvious, edges were chewed up. Had prop fixxed and all was well. and I thought the same think when I looked at the shaft vs. the position of the rudder. It was on my first MC an 88 tristar.
I agree with your perspective on the incident. It makes me think I should get a spare prop.

07-29-2008, 08:02 AM
Re: spare prop....if you had had one, you could have quickly gotten an indication of the condition of your shaft and strut by putting the new prop on and seeing if you have vibration or steering issues.

07-29-2008, 09:23 AM
That second picture looks like the prop is bent. Maybe it's the angle of the picture but that lower blade looks bent to me.

east tx skier
07-29-2008, 09:49 AM
You, sir, have a bent prop. When we did that to my father-in-law's prop, we sent it to OJ for repair and it came back better than new (and I mean it ran smoother than before I hit something).

07-29-2008, 10:36 AM
That being the case do I need some special tools to hold the propeller shaft to remove the bent prop?? I've never changed the prop on an inboard

07-29-2008, 10:45 AM
That being the case do I need some special tools to hold the propeller shaft to remove the bent prop?? I've never changed the prop on an inboard
No special tools. You don't have to hold the shaft, holding the propeller is all that's necessary. They're kind of uncomfortable to grab the edge firmly with one hand while wrenching with the other, so I'd wrap a towel around it. You have to be careful of your hands, you know...

07-29-2008, 10:47 AM
Holding the prop with your hand should suffice, but you can always wedge the prop with a broomstick between the strut and the rudder to pull the wrench with both hands.

07-29-2008, 01:08 PM
I just wedged a 2x4 between a prop blade and the ground - the force on the prop is then directed along the chord of the prop, where it's strongest.