T&T: premature impeller failures

Sean Welsh slwelsh+trawlers at gmail.com
Mon May 25 16:11:20 EDT 2020


> If the wear plate you are referring to is the "cover plate" that 
> mounts to the outside of the pump housing which the impeller spins 
> against, then I already replaced that because we thought that the 
> scoring on the original one might be causing the impellers to break 
> prematurely.

No, the wear plate is at the other end. As you can imagine, if one end 
of the impeller has worn the cover plate, the other end has worn the 
wear plate. I did read that you already replaced the cover plate.
>
> As to changing the "cam" I would have no idea how to do that and it's 
> highly unlikely that I would find one here in St. Lucia.  If it's the 
> cam (I could maybe get someone here to look at to confirm that) I 
> could put it on my parts list for my shipment in from the states.
>
>
The cam is the part that makes the chamber out-of-round and is 
responsible for the pumping action. It's easy to see with the impeller 
out. Most cams come out with a single screw that threads in from the 
outside of the chamber. The cam has to come out to get to the wear plate.

I will forewarn you that some smaller pumps have the cam essentially 
cast into the pump body. These pumps are disposable; you have no choice 
but to replace the whole pump when worn.

-Sean



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