Raw water pump or circulating pump

How can I tell which pump is bad. End of last season I had a squeaking sound coming from one of the pumps.I could not determine which pump was makin the sound.I want to fix it before the boat goes in this spring.Any suggestions on findingwhich is the bad pump.?? The boat is still winterized. Thanks Mike

Remove one belt at a time.

Jeff

Many times you can feel the friction in the bearings while rotating the drive pulley with the belt removed. If it is fresh water cooled and the coolant has been maintained, I'd start with the raw water pump.

Need more info from you.
Raw Water cooled, or Closed Cooling system?
Belt driven sea water pump, or crankshaft style sea water pump?

Like suggested, remove the Circ pump belt, and fire the engine up for a short duration. If the noise goes away, then that's the pump whose bearings have gone bad.
If no change in the noise, then it's the belt driven sea water pump (if equipped with this style pump).

If you have the crankshaft sea water pump, you can grab onto the pump body and see if you can make it wobble.


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The motor is fresh water cooled 1989 crusader 350 270 hp and its a belt driven pump. I took off the raw water pump today, spun the pulley seemed smooth no sounds and there was no play when I moved it back and forth. I also removed my oil cooler bracket today which uses the same bolt to hold the bracket and the circulating pump. When I removed the bolt I started to leak antifreeze from the bolt hole, is this normal. Thanks Mike

To be fair and thorough, you need to remove the impeller from the raw water pump to assess its bearings. BTW, those are normal maintenance items.

If you loosened the oil cooler's mounting bracket bolts (same ones holding that side of the circulating pump), then some coolant escaping from those holes is normal.

Not meaning to hijack the thread but the answer may be pertinent here. I have been hearing a faint but noticeable sound coming from the front if my engine too. May sound as if you layed a very light screwdriver on a pully. I suspected the raw water pump and rebuilt it. Still the noise is there. Now im thinking circulating pump. It doesnt leak through the weep hole. If i remove the belt and the pulley doesnt wobble can i assume its ok?

take a long screwdriver and touch either pump with its tip and then put your ear to the other end of it. you can usually hear the bad bearing noise through the tool kind of like a stethoscope.

Found the bad pump. It was the raw water pump.Thanks for all the help. I went down today and took the raw water pump off along with taking the impeller out. I was able to move the shaft back and forth, had alot of play in it. Guys thanks again for your help. Mike

makomike1 said:

Found the bad pump. It was the raw water pump.Thanks for all the help. I went down today and took the raw water pump off along with taking the impeller out. I was able to move the shaft back and forth, had alot of play in it. Guys thanks again for your help. Mike

Click to expand...

Mike, most or many of these lend themselves to a bearing replacement.
Often the bearings and seals are industry standard...... and are very easy for a major bearing supplier to provide.


FYI:
Depending on which engine model you have, some of these belt driven sea water pump systems can be circumvented in lieu of a crankshaft sea water pump.
I've walked many people through the procedure.
To do this, you must have a minimal amount of space FWD of the front crankshaft pulley, minus the belt driven pump pulley.

A friend of mine needed to replace a pump on his Merc 6.2L Horizon. Merc wanted over $600 for a new one, and the new pump was several weeks out.
We spoke, and I mentioned converting to the Johnson F6B-9 pump.
He chewed over the idea, and that's what he ended up doing, and he's happy as a pancake with it.
Easy impeller access, and there is no belt tension side load to tug away at the shaft bearings.

This is a Chrysler Marine engine related thread, but the front crankshaft pump idea is very similar.

Food for thought if nothing else!


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Mike, here's a Volvo Penta AQ260 5.7L Raw Water cooled engine.
The crankshaft pump mounting is identical between this and the AQ260 with a Closed Cooling system installed.

But again, you need the space ahead of the engine in order to make this work.





Here's an Indmar 6.0L with a crankshaft pump.




DaddyO's Marine is selling these packages w/ the crankshaft pump.



Their Crusader version.



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