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Bravo 3 OEM Mercury prop issue - appreciate input

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ebg338

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Looking for any input on this. Pulled my props for cleaning this year and noticed an issue with my rear prop (OEM Mercury 48-823666 24P). You can see in the pic (Prop 1) there's damage to the spline, a hole and some cracking - haven't had the boat long so prior owner could have hit something or had an issue. No impacts/issues during my ownership so assume this was existing. Prop shows no other damage and other than needing a polish in very good condition (other than the issue in the pic). That said I bought a used replacement prop (again, OEM Mercury 48-823666 24P) - looks to be in very good condition but upon cleaning the valleys between the splines I found a similar hole and cracking (Prop 2). Both props have no other visible damage. Very odd to me that both are in very similar spots on the prop - they align with one of the 3 supports to the inner barrel and are in approximately the same spot. Also, the splines on the sterndrive are in perfect condition. Wondered if this could have anything to do with the casting process? Anyone seen this before? Any thoughts are much appreciated. Thanks
Prop 1.jpg
Prop 2.jpg
 
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Pictures would help, but going by what you describe I'd lean toward the casting and not an impact. Two different props with the same flaw in the same place, both times lined up with one of the ribs into the barrel... that's the thick part of the casting, and the thick sections are what freeze last, which is right where shrinkage voids and porosity like to show up. Something striking the prop wouldn't pick the same spot on two of them, and your drive splines being clean kind of backs that up...

SWAG on my part though, I'm not a prop guy...

That said I wouldn't run a cracked hub without somebody looking at it. A round smooth void is one thing. A crack with a sharp end is another, and those do grow. I'd carry both of them to a prop shop and let them have a look, they can dye check aluminum in a couple minutes. Cheap next to losing a prop at speed...

Does it slide on and seat without any rocking? Any play fore and aft once the nut is torqued? And does it shake at all once you're up on plane...

Keep us posted on what the shop says, curious to hear. Thanks
 
Thanks for the comments. Based on what I'm seeing I wouldn't run either of them, the voids are irregular and I can see cracks extending beyond them. I attached 2 photos in my original post - are they not visible?

Also, given the luck I'm having wondering if there are recommendations for an alternative / new prop (or props if I need to change both if they need to be a matched set) for my setup. Running a 2006 350 MAG MPI with the Bravo 3 in a Bennington 2875 tritoon - I'm very satisfied with the performance with the current prop setup but starting to worry about sourcing another used one.

Thanks
 
I haven't seen damage like that before but being the B3 props are solid stainless it could have just been a defect in the casting that later showed up after machining. I would run them without issue if you don't see marks on the prop shafts
 
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