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Pulley bearing noise, which one?

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BarryK3

Contributing Member
Hi all,

An issue on my other engine. Approx. 1991 Gen 5 454. There is a loud squeaking noise from the front of the engine after it warms up a bit. I assume it is a bad pulley bearing. How do I isolate which one? The belts seem to have proper tension. Fresh water pump vs. raw water vs. alternator?

Thanks,
Barry
 
you can remove the belt to isolate the raw water pump from the circulating pump and alternator....regarding separating the source from the circulating pump or the alternator, when you remove their belt, both should be free and any roughness felt while manually rotating the pulley should indicate the culprit...
 
Thanks Makomark!

I removed the belts. The fresh water pump pulley was completely fine. The alternator pulley is minimally bent (wobble) but turns smoothly. I think it is fine.

The raw water pump pulley was very difficult to turn. I removed the pump and took out the impeller. The pulley was still very difficult to turn, almost frozen. I think I have my diagnosis. I sent the pump out for a rebuild.

Thanks again!
Barry
 
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Barry said:
I removed the belts. The fresh water pump pulley was completely fine. The alternator pulley is minimally bent (wobble) but turns smoothly. I think it is fine.

The raw water pump pulley was very difficult to turn.

Barry, you should have only three belt "driven" devices with pulleys.

....... engine coolant "circulating" pump as Mark alludes to
....... alternator
....... seawater pump (if belt driven)


I removed the pump and took out the impeller.
The pulley was still very difficult to turn, almost frozen. I think I have my diagnosis. I sent the pump out for a rebuild.

Barry, if you have the space in front of your harmonic balancer, consider going to a Johnson F5B-9 or F6B-9 crankshaft style seawater pump!
This style pump has no side load against the shaft (from drive belt tension), of which allows the shaft bearings to last much longer!
They will typically outlast any belt driven seawater pump.

You rid yourself of one pulley and the related drive belt as well.

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Thanks Rick!

This looks like a great option. Let me see how things work when I get the rebuilt pump back and start the engine again.

Barry
 
So, I sent the raw water pump out for a rebuild: rawpumps on eB*y. They did an awesome job for a reasonable price. New bearing, impeller, bolts, paint etc. I reinstalled it a few days ago and no pulley noise! I also put in a new hose from the V-drive to the pump. The old one was in bad shape with a flat spot possibly obstructing flow. The hose from sea cock to V-drive is also new.

Thanks everyone for the help!!

Barry
 
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