has this happened to you

So I have been feeling some vibration in my boat latety, and everyone has been telling me its most likely the prop. I inspected it and everything looked fine, except when I went to inspect it, it had about a quarter to half inch of play/rotation. I thought to myself 'well its probably normal to have a little play' but when I went and visited a local boat dealership they told me it should be solid especially for being a newer boat. They told me 2 things,
1. Check to make sure the shaft isn't turning and if it is I might have something wrong in the v-drive unit.

or 2. If it is just the prop that is turning there are these key grooves the prop slides into which holds it tight and maybe they got worn or the prop is worn where it slides into the grooves.

I think I have issue number 2, and my guess is that I will have to pull the prop off and inspect it, and if the grooves are worn then take it in to get re-machined or something like that.

Do Centurions use a keyed shaft or splined shaft? If it's a keyed shaft, maybe your key is worn or has the incorrect one being used. I would check the key before machining anything. If it's splined...

No you are right they have a keyed shaft. What should I look for it the keyed shaft is worn, or has the incorrect one?

I would just make sure they fit together well. It's a clearance fit (side-to-side), but should have too much clearance. Check the key to the shaft and the key to the prop. Look over the key, prop, and shaft for any general damage. I don't think keys are vert expensive and unless they are something special you should be able to pick one up at an auto store or TSC.

One other thing. Is your prop snug to your shaft front to back? There should be a taper on the shaft that kind of ends up press-fitting to your prop. Make sure (by hand) that connection is tight too.

Paul thank you for all the advice, I'm trying to visually in my head understand that last thing you mentioned with whether or not the prop is snug on the shaft? Do you mean apart from me rotating the prop a little on the shaft, does the prop move up and down along the shaft. If that is what you mean no I don't think so but I will double check. Also not sure about this taper you are talking about, I haven't spent enough time really looking and understanding the way the prop is connected to the shaft. If I remove the prop I'm sure things will become a little more clear.

Do you know of any visual aids you can point me too, that might explain this more?

I just took my boat in for a similar problem and it was the shaft coupler in the bilge coming out of the v-drive unit. Damn hard to see down there. Anyhow the prop shaft nut was coming loose. cost me an hour and a half of labor for diagnosing and fixing.

Stated in my first post about issue 1, thats exactly what the person at the dealership told me that it could be the shaft coupler. I checked my shaft when I got home and there was no movement in it just the prop. Just for curiosity how much did it end up costing you Kelly? Thats also interesting because you have a supreme and my issue is with my avalanche which are made by the same company if I'm not mistaken. My avalanche is an 05

sounds like maybe your prop was just loose and should have the bolt cranked on...use some wood blocks to wedge the prop so you can get leverage to tighten...

it should always be a pressfit solid connection...thats why you hear of prop pullers...

Steve,
Check this out for visual images. I'm not saying this is preferred method (I didn't read), but just some good visuals that came up in google.

Check here...

I pulled the prop yesterday and I found my key to be worn pretty bad, which I believe has been causing the vibrations. Taking it to a prop shop today see what they can do. Paul thanks for the info, I will take that diagram with me in case they need to machine the key or the prop so they don't screw up.

Steve,
No problem. I hope you get it resolved quickly and cheaply. If it's just the key, you should be good.
Ask the guys at the prop shop about putting some sort of waterproof grease on the key to fight corrosion.
Take care,
Paul