Looks to be the same pump. I pulled it and spun it up to probably 100 rpm to see if I could replicate the knock and it wouldn’t reproduce the knock. It wasn’t under load by the belt and pulley so that might be the difference. I also pulled the belt and ran the engine a second to isolate the noise. Definitely the pump! There is about a 1/4” rotational play in the pulley until the impeller engages so that might be an indicator. There is no discernible run out on the bearing or end to end play either. I am heading down to the dealer this morning to see what they say. I did find a rebuild kit, I believe… so I will try that cheaper option first. The dealership years back said they wouldn’t mess with the rebuild kits it was too time consuming vs a new pump. Understandable from a warranty work perspective it’s a 10 minute job max to swap the pump, not so much from an out of pocket perspective.

Thank you all for the help. I update this thread when I am finished. 

I like what everyone said. I did it in my 2003 about 3 years ago.  There were a lot of zip ties that needed to be cut (like 6-8)

A google search shows this as a 1505, it does have a different second number on the plate:

https://marinepumpdirect.com/sherwood-pump-p1505-replaced-by-p1505-01-pump/

From Malibu Parts:  https://www.malibuparts.com/products/impeller-malibu-m-series

Does this one look like the one on your engine?  Best I can tell, it uses the same impeller as the typical crank mounted F6-9B pump found on most engines from Indmar, PCM etc.  The difference looks to be the way it mounts and what drives it.  If it is your pump, they don't exactly give them away and if you add some dealer markup, ouch.  Can you remove the pump  and determine where the problem is?  You could remove it, pull out the impeller and spin it to see if the bearings are faulty based on what your description seems to indicate.  I can't imagine a set of bearings / seals would be very expensive.  Good luck.

I love law makers! But a question,

If I put my wedge on "full, semi automatic" mode, would this law apply if it passes?

Good Morning everyone!

I have a 2008 Malibu 23 LSV. 

I went to change the packing and somehow the nut won't thread back on. I went ahead and ordered a dripless. 

My problem is getting the coupler off. I know this has been in other threads but they are all old and different than mine.

I don't have any set screws. I do however, have a weird locking collar. Does anyone have experience with this and advise on how to remove it? I am goin g to heat to it today and see if I can slide that collar off to get to the nut. I know how to lock the shaft to get enough pressure to back it out.

If you look in the diameter photo to the coupler where a set screw should be I see nothing in there. So my deduction is that it is only the tooth collar in great holding the bolt on.

Thank you in advance!!