What could cause this?

Oct 29, 2005
2,355
Hunter Marine 326 303 Singapore
When my pulley hole rounded, for emergency repair I fit a star washer. It works.
Suggest you put a star washer in so that it bites into the pulley for added security.
 
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pateco

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Aug 12, 2014
2,207
Hunter 31 (1983) Pompano Beach FL
So, It has happend again, now with the second water pump I have.

Two weekends ago, after I had just finished up doing a fuel filter change, and restarted the motor, i noticed I had no water flowing out my exhaust. I stopped the engine and spent 10 minutes swapping it out for my spare water pump. This solved the cooling issue, but left me with a pump to overhaul. When I took it apart, I noticed two issues, both requiring new parts.
  1. Impeller (only about 6 months old) lost a fin, and the fin had jammed itself into the water outlet.
  2. Jammed impeller somehow managed to strip the keyway cuts in my pump pulley, allowing it to spin under load.


So I picked up a new impeller locally, and ordered the pulley from Toads. Got it put back together and it is now in the spares box.

This is the second pulley that I have had to replace for this very reason, so now both of my pumps have brand new ones. Have any of you had similar issues with the pulleys?

How long do your impellers last?

When my pulley hole rounded, for emergency repair I fit a star washer. It works.
Suggest you put a star washer in so that it bites into the pulley for added security.
After rereading this thread, I think I will go and get two star washer as you suggest
 
Dec 2, 2003
751
Hunter 260 winnipeg, Manitoba
From photos earlier it looks like the shoulders on the shaft may be rounded off? Not sure if this is from factory as a safety feature to prevent damage to pump when it jams - allowing hub to spin or if it is just worn - causing the pulleys to spin easier. Perhaps have a look at a new factory shaft?
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
I am having a hard time imagining a rubber impeller vane jamming the pump shaft with sufficient resistance to round the pulley keyhole. I have seen jammed impellers strip the rubber impeller ring from its bronze shaft hub. In any case, an impeller should easily last a long season or several hundred hours. I also noticed that the bearing shaft looks worse for wear and tear. At this point I would consider a new pump with all new bearing and shaft. Bearings will spin fine without load but jam with a load - that is a real possibility here.
 
Nov 26, 2012
1,653
Hunter 34 Berkeley
The hole does look awfully perfect. With that said I know that the steel that the pully is made of is pretty soft. When I rebuilt mine a couple of years ago I wallared (sp?) it out just trying to get it off. I'm guessing that, in your case, it was slipping for awhile with the pump still operating in a limited capacity all the while making the hole more perfectly round. Could have started with something clogging up the impeller causing it to load up.
 

pateco

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Aug 12, 2014
2,207
Hunter 31 (1983) Pompano Beach FL
Could have started with something clogging up the impeller causing it to load up.
Broken fin forcibly stuck in the water outlet had the impeller jammed nicely. I had to use needle nose pliers to get the fin out after removing the old impeller.
 
Jan 30, 2012
1,123
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
The washer/spacer is important. But round or squared off it must hold the pulley away from the pump body so there is no interference one with the other.

More common - since the pulley drives the shaft - if either bearing is failed the pulley engagement hole starts to enlarge and then it is just a matter of time. If the shaft does not turn silky smooth - impeller out - replace both the bearings. If you are in the slightest doubt or feel the slightest tick or bump as you turn the shaft replace the bearings. This is a very simple job - just mind the slinger between the bearings and the seal (it keeps the water out of the bearings in case the seal weeps). Replace the lip seal too the garter spring goes toward the cover.

Obviously the broken impeller is a problem - so find out why these keep breaking - these should last 500 hours easy. Most the time it is a start/run without water that causes the failure so check that you open the intake, that there is no leak in your strainer, and that the surfaces in the pump body are smooth.
Charles
 
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NYSail

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Jan 6, 2006
3,048
Beneteau 423 Mt. Sinai, NY
I too can’t wrap my head around how this could happen. Are you over tightening the belt?
Greg
 
Jan 5, 2017
2,263
Beneteau First 38 Lyall Harbour Saturna Island
if either bearing is failed
Sometimes bearings can feel good most of the time and still jam under load because the ball cage is broken. The engine is driving the pulley so it must be the pump that is the fault.