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Tony
05-31-2001, 09:21 PM
According to Einstien, a pole vaulter carrying a 12' pole, running at the speed of light, could be captured in a 10' double door garage...presuming the doors could close fast enough. Here's my similar situation:
In my garage, there is clearance between my new zinc ring and my new Ultra, on the tail end of my old Volvo AQ200. After running, though, I find that my zinc ring, and screw heads that attach it, are scored from the prop rubbing on them!
Is my thrust washer compressing? Is there a rubber hub in my prop that allows slight forward movement of the prop while underway? What's going on? Any Einstiens out there that can explain this to me?

Forrest
05-31-2001, 11:00 PM
It the rubber hub compressing. Get ready for a re-hub job. Admrial Propeller in Tampa can upgrade the hub for about $85. The job requires machining and they've done the job a number of times.


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Forrest

Tony
06-01-2001, 11:11 AM
Is a little compression in the hub normal? I ask this because I just bought the prop, although it was sold as a "reconditioned" prop. Would reconditioned necessarily mean the hub has been reworked?

Forrest
06-01-2001, 01:18 PM
A little compression may be normal since it is made of rubber. Without looking at it, it would be hard to say if the hub has been replaced. Most hub upgrades for Volvo props are made by Michigan Wheel.

Tony, if you have a digital camera, take a picture of the outdrive side of the prop and post it here. The hub upgrade looks different than the factroy hub from that side.

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Forrest

[This message has been edited by Forrest (edited 06-01-2001).]

scooter
06-01-2001, 05:46 PM
are you sure your are not having cavitation burns? the thrust washer would not compress.

Formula Jr
06-02-2001, 10:12 PM
Scooter, compression is probably the wrong word here. More like forward deflection of the hub, relative to the stationary prop shaft. In other words - if I'm reading correctly- Tony's prop is moving forward under stress, deforming the rubber hub enough so that the prop is rubbing against his zinc on his lower unit. Without the stress the prop spins fine with no interference with the zinc. I don't know if he can shave the zinc, If he can't then the prop needs rehubbing to place it further back on the hub. You'll note that Mercs recess this area on the prop so the prop can move in and out relative to the lower unit with out too much concern for tolerances, and the new type hubs use a plastic insert so there's no forward movement.