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I can not believe the difference in the way my boat handles by just changing the prop. The hole attitude of the boat changed. The bow rides about 10 inches higher with this prop.
I did notice when changing the props the new one didn't go on the shaft as far as the old one. The taper must not be bored as deep.
As far pitch im not sure what I went from. They are both 15 inch. The one I put on says 11 1/2 by 15. The old one is so rusty you can't read it anymore.
I need to get my tach fixed so I know what rpms im at.
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The first number is usually the size, the second is usually pitch - sounds like a set of 11 1/2 props, and the second is a 15 degree pitch. Make sure the key didn't pinch as for the reason your prop didn't go all the way on....that doesn't sound right. It could be the keyway in the new prop is not as deep and the old key (or a new one) is stopping the prop from seating as the taper is pinching the key before the shaft fully seats. Try putting the prop on without the key and see if it seats to the shoulder of the shaft - that will tell you if you might have a key issue. A lot of times you have to fit the key with a grinding stone - a bitch but worth the hassle. A lot easier than diving to find your new prop or shearing a key and watching an unscheduled disassembly while you are driving it.
If you know all this please disregard. If not there is a great thread on installing a new prop and fitting the key/shaft here somewhere but I could not find the link.
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I just went thru that scenario on the PS52 boat, new shaft and they never fit the prop and it didn't go all the way on and it was actually crooked, the result it bent the shaft in two places and was ready to break at the strut!.. ALWAYS put the prop on first without the key when you change props and when you put a new shaft in!..
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I will check it out. My reason for thinking the bore was deaper on my old prop was because the old prop nut had about a 1/4 inch from the nut to the cotter pin. The new one was so close to the cotter pin it was hard getting cotter pin in.
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Another thing that I was told to do in addition to checking the prop without the key is to put some valve lapping compound in the prop taper and spin the prop around a bit to shape the prop to your drive taper...
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Another thing that I was told to do in addition to checking the prop without the key is to put some valve lapping compound in the prop taper and spin the prop around a bit to shape the prop to your drive taper...
Do that and mark the shaft with a marker with the prop on no keyway then file the keyway till it lines up with the marks snug fit.
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Do that and mark the shaft with a marker with the prop on no keyway then file the keyway till it lines up with the marks snug fit.
Posted by Dossangers
This is how I was taught to do it.
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Ok.. I've got a prop that doesn't go on the shaft by 3/16 in. as compared to the old prop. This is the same with or without the key. I haven't checked with the valve grind, hadn't heard of that. So, does this mean anything?
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I have had props that were drilled at different depths. I have a Hill prop that is drilled deep and I need two washers on it so I do not run out of threads. As long as the key fits in both the prop and shaft, I think it's harmless.
The only issue might be how it would make the boat behave, sitting more fore or aft than intended. Of course, props are such voodoo anyway. If it's working for you, stay with it.
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I had a Hill prop I let go with the boat, I had to make a spacer for it but it was because the hub was way shorter, it still went up the same distance on the shaft though!..