Fitting a new propeller

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crown22

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Hello Everybody
My new propellor 13 by 9 will be here soon I I can't find anybody to fit it for me so will be doing it myself.
Slide the prop onto the shaft using the keyway. Tighten the nut and then fit and bend back a new split
pin.Only potential problem I envisage is if the new prop is a slightly different thickness than the old one
that I won't be able to line up the split pin with the hole in the shaft and the cuts in the top of the nut.Any
suggestions if I have overlooked something much appreciated.
 
You don't need to tighten the nut up excessively, slide the prop on the shaft and give it a good push once it is located on the key, that will ensure that it is mated with the taper which is what drives the prop not the key. Then spin the nut on by hand till it buts up against the prop if you can get the split pin in do so if not just nip the nut up it shouldn't be much a castellated nut will have 12 or so slots. The alternative is a locking washer, the pin and the washer are there just to stop the nut unscrewing nothing more and the nut once it is gently seated against the boss of the prop is fulfilling its function it is not designed to force the prop up the taper.
 
As Fr Hackett implies, one of the big no-nos of fitting a prop is that it should seat fully on the taper, rather than hang up on the key. Best to offer it up first without the key, mark where it sits, then fit it with the key: it should sit in exactly the same place.
 
If the castellation on the nut is too loose in one position and too tight in the next, the best solution is to use a second washer as a shim. I did this a couple of days ago with a Land Rover transfer box output shaft nut before realising that the shaft has two split pins drillings at right angles so if one is not quite right, the other can be tried. However, I don't think this is very common.

Richard
 
Either tab washer or Nylock nut are OK especially if the boss length is different on replacement prop.
Very reputable replacement sterngear companies use these methods to secure props on engines producing several hundred horsepower.
Quick, simple and inexpensive compared to faffing around with washers and split pins and as for having to re drill shaft...:(
Only downside....you need to know the thread.
Search online, can be ordered over the phone and be with you within 48 hours.
 
Last edited:
prv said:
I'd be happy with a tab washer, but there's a shiny new prop somewhere on the bottom of Portsmouth Harbour that was "secured" with a nyloc to a boat I know.

Pete
Click to expand...

They probably didn't tighten the nut sufficiently.
 
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