Key and key way question

[dwna1a]

So, I took my baby over to pump out and I heard a odd noise. I figured the zinc had slide down the shaft and was hitting the strut.

The diver went under her today and found that the key is missing from the key way. The prop was moving on the shaft.

How does this happen? She was fine when she was put away. Could the really low tide have sheer the key or this winters ice?

 

[FootballFan]

Was a worn key used the last time the props were off?

Was the correct key used?

 

[dwna1a]

Worn? Maybe, it has been in there a good long while.

Props were off in early Fall if I remember correctly. They went on easy and the key was good and tight. No play in the prop.

Bad part for me is that I have to drop my rudder to get my prop off. This isn't a easy fix. She will have to come out.

 

[blaster]

That is unfortunate as we are finally getting a warm-up. I hope you get those props spinning strong soon.

 

[Woody]

So, I took my baby over to pump out and I heard a odd noise. I figured the zinc had slide down the shaft and was hitting the strut.

The diver went under her today and found that the key is missing from the key way. The prop was moving on the shaft.

How does this happen? She was fine when she was put away. Could the really low tide have sheer the key or this winters ice?

If there's no key in the keyway it means someone forgot to put one in, they can't just fall out.

 

[hottoddie]

If you can get the prop loose with dropping the rudder you may be able to slide a key from the front and then reseat the prop. May be worth a try.

 

[dwna1a]

If there's no key in the keyway it means someone forgot to put one in, they can't just fall out.

Woody I would think that some of the key is still there. The prop won't just free turn on the shaft. She comes out next week and I will get some pics.

 

[sbw1]

Woody I would think that some of the key is still there. The prop won't just free turn on the shaft. She comes out next week and I will get some pics.

Count yourself lucky you found out about it in such a benign way.

 

[dwna1a]

Only big fear is that the key way on the shaft or prop is damaged in some way.

As I said, she comes out next week and I will try to post some pictures.

 

[Woody]

The diver went under her today and found that the key is missing from the key way. The prop was moving on the shaft.
How does this happen? She was fine when she was put away. Could the really low tide have sheer the key or this winters ice?

If your shaft and prop hub bore were in good condition, that wouldn't have changed throughout the storage months. If the propnut is tight even without a key you shouldn't be able to move the prop. Sounds like at least the prop nut has loosened. Good luck with it, hope it's not an expensive repair.

 

[dwna1a]

Woody that is the side she settled on when we had those very low tides, could the weight of the boat and the forces under the boat have sheer the key?

I just heard that another boat behind mine is having the same issue. 400EC has sheer the key off. He is getting it fixed by the diver then taking the boat to get hulled. He is just as perplexed as I am.

 

[Boater420]

Would contraction from the cold have opened up a gap between the shaft and prop hub big enough for the extreme pressure to maybe "round off" the top of the worn key and allow it to move past the slot ???

 

[PlayDate]

That just doesn’t make sense. Without a key and a loose prop you would have zero thrust on that side. I’m curious what you find when you pull the boat.

What might have happened is the prop is just loose and the key is still there. I’m also curious why the diver would say the key is missing and why he didn’t try to tighten the prop nut.

 

[dwna1a]

That just doesn’t make sense. Without a key and a loose prop you would have zero thrust on that side. I’m curious what you find when you pull the boat.

What might have happened is the prop is just loose and the key is still there. I’m also curious why the diver would say the key is missing and why he didn’t try to tighten the prop nut.

All he said was that he couldn't feel the key. Now I'm curious about the prop nut. I'm hopeful to be out by Wednesday but they are very busy and I'm not going to push. If the sheer pin is still in place and the outer nut didn't move how would the prop nut back out?

 

[Woody]

All he said was that he couldn't feel the key. Now I'm curious about the prop nut. I'm hopeful to be out by Wednesday but they are very busy and I'm not going to push. If the sheer pin is still in place and the outer nut didn't move how would the prop nut back out?

I don't know what happened to your prop, can't wait to find out but it's possible neither nut moved. During prop installation if the key was pushed forward to far and started climbing the keyway radius then your prop would not go on all the way. Eventually during use things might work toward their proper position and now the prop would be loose. When installing your prop do it first without the key and mark with a sharpie. Then when you put it on with a key if the prop goes all the way to your mark you'll know there's no interference from the key or anything else.

 

[PlayDate]

All he said was that he couldn't feel the key. Now I'm curious about the prop nut. I'm hopeful to be out by Wednesday but they are very busy and I'm not going to push. If the sheer pin is still in place and the outer nut didn't move how would the prop nut back out?

I'm not sure what sheer pin you are referring to (presuming you have inboard drives). If you mean the cotter pin...there is enough space between the outer nut to back off before it reaches the cotter pin which results in a loose prop. Basically, two things can cause a prop to come loose: 1) a misaligned original installation 2) hitting something. Of the two, the first is the most common if the key, shaft and prop are not seated (Woody suggested a great way to do that) then it is only a matter of time before it gets loose.

A loose prop generally won't make any noise when you are in Forward drive since the prop is pushing water and being forced up the shaft (you may feel a vibration). However, when you use reverse.....you can hear a loose prop rattle on the shaft.

 

[fwebster]

If you had an original OEM key, then they are doweled or fit in a shaped keyway like the photo below. The dowel pin sits in a drilled hole in the keyway and the shaped key/keyway keeps the key from moving during and after installation. In either case the key won't come out even if the prop nut is loose. If it is loose, the prop is forced up on the shaft taper when in forward and the boat operates normally, but in reverse when you put the transmission in gear, the prop slides aft and contacts the loose prop nut, and you may feel a slight bang and hear a clank when you first put it in reverse and feel a chatter when in reverse.

I think this one will be a mystery until you pull the prop. In any case, check to see if your shafts are drilled for a down pin in the key oir require a shaped key and if they are, get (order) the correct key for your shaft.

 

[dwna1a]

She comes out tomorrow. I may not be able to be there but the staff will let me know what the find

 

[dwna1a]

Members, I did not get pics. I'm sorry.

The prop was loose on the shaft due to the inner nut backing off the prop. The key was fine but is being replaced the key way was fine.

The prop was bent, I have no idea how or when but I must have hit something at the end of the season. It's gone to Murphys prop over in Chesapeake.

Thank you all for the suggestions and help. I'm still just as baffled but she is under repair.

 

[PlayDate]

I really am surprised that your diver didn't sort this out for you. Most of the divers I have worked with inspect the prop and will remove it if it is damaged or tighten it if it is loose.