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View Full Version : Prop can move about 1/16" to 1/8" on shaft.


trayson
06-28-2015, 06:08 PM
So I noticed the other day that I can grab my prop and rotate it about an 1/8" on the shaft without the shaft moving. The key is in there and the nut seems tight (like I can't really get it tightened down any further, it's certainly not loose...)

If you look at the top of this pic, you can see the key is in there.
https://lh3.googleusercontent.com/-RO3r8ar22TE/VZBtoxIKYuI/AAAAAAAAZis/_-szB2DrkuE/s800/20150628_144933.jpg

This is how the prop is sitting on the shaft:
https://lh3.googleusercontent.com/-Q1DTCRc_s2s/VZBtmJ2DkBI/AAAAAAAAZic/SB_UPoDW2vg/s800/20150628_144953.jpg

This is from the back side of the prop. you can see that the key is in there, but it doesn't extend all the way to the end of the prop.
sorry for the pics, but not the easiest shot to capture.
https://lh3.googleusercontent.com/-avvFARPzpOE/VZBtnUoJVxI/AAAAAAAAZik/O9tEXw-PH4I/s800/20150628_145254.jpg

https://lh3.googleusercontent.com/-wIsNNTxYqZo/VZBtqohPJmI/AAAAAAAAZi0/E7UnRyPp3Sg/s800/20150628_145154.jpg

The boat seems to perform just like it always has. The only reason I noticed that the prop could move back and forth about that 1/16th to 1/8th inch is because there was some seaweed wrapped around the prop shaft behind the prop that I had to take off after taking the boat out of the water.

When I tighten down on the prop nut it stops the ability for the prop to jiggle back and forth, but that doesn't last as I'm probably not really getting the nut any tighter, just making the prop's inside channel wedge against the key.

Thoughts on this?
MLA
06-28-2015, 06:30 PM
Prop is not fully seated on the tapper, i can see the witness mark from the old prop in pic #3
trayson
06-28-2015, 06:43 PM
So I assume I should try to get the nut to move? and get the prop seated further on the shaft and make the nut tighter?
MLA
06-28-2015, 06:54 PM
You need to get the prop to seat without using the nut as a press. Continuing to run can shear the key and bugger up the prop and shaft.
muehlcj
06-28-2015, 07:37 PM
Take the prop off and remove key. Slide the prop back on with out the key until it stops. Mark the shaft. Put the prop back on with the key and make sure it slides all the way back to the same spot. If not the key may not be completely seating in the shaft or the prop and you may need to file it.
DOCDRS
06-28-2015, 08:11 PM
Take the prop off and remove key. Slide the prop back on with out the key until it stops. Mark the shaft. Put the prop back on with the key and make sure it slides all the way back to the same spot. If not the key may not be completely seating in the shaft or the prop and you may need to file it.

That means your nut is tight on the key????? If the prop can move in and out away from the nut. The key way is tapered so the key can/ should not bind up on the strut. Something is not right here. If the prop is moving on the shaft, the key is not binding between the prop and the shaft. I would check the torque on the nut , it is listed in the specs
mnpracing
06-28-2015, 11:15 PM
Key in backwards?
VA LSV
06-29-2015, 08:32 AM
The shaft is tapered so the shorter (angled) side of the key needs to be down in the shaft keyway and the longer side of the key needs to be facing up into the prop keyway.
MLA
06-29-2015, 08:34 AM
key is not tapered, but square.
kaneboats
06-29-2015, 09:31 AM
You probably have wear on the key at this point too. Should consider replacing it when you take it apart to do the above.
VA LSV
06-29-2015, 11:22 AM
New keys from Ski Dim are chamfered.
http://www.skidim.com/searchprods.asp

Shaft and prop are tapered so it sounds like the something is keeping the prop from seating on the shaft.
trayson
06-30-2015, 10:20 PM
You probably have wear on the key at this point too. Should consider replacing it when you take it apart to do the above.

So I ordered a prop puller, and the new key/nut/cotter-pin from Wakemakers yesterday and true to form, I had it delivered to my house in under 24 hours with free shipping.

I believe that my key was worn. The old key was a lot looser in the channel of the prop and shaft than the new key. I found it odd that the old key was almost as long as the prop (1/4" less). And the new key was about 1/2 the length of the prop. But I guess the key doesn't need to run the whole prop length to do its job.

I reassembled the prop with the new key/nut/cotter-pin and we'll see if it does better. I think by the fact that the new key was noticeably more snug that I'm probably in the clear on this one.

I guess now I have a prop wrench and prop puller. not bad tools to have considering you're dead in the water if you can't pull your prop when you need to.