Back flush from raw pump

[WOJO 1]

I have done a bit of reading on here but i need to ask this question. Can you back flush from the raw water pump out through the lower end of a Cobra SX? Just to make sure there is no obstructions in the lines or the oil cooler. I don't need to damage anything. My motor is getting hot (even though the gauge does not show it). I did a raw water pump check by taking off the hose that goes from the pump to the t-stat housing. The manual says there should be a 2"-4" column of water while the engine is running in idle. I have no where near that. Maybe less than an inch of water out the hose. The impeller looks good and is not that old. The fins are bent when I took it out but is still plyable with no cracks in it. Sorry for the long post but any help is appreciated.

 

[Bondo]

Re: Back flush from raw pump

The fins are bent when I took it out but is still plyable with no cracks in it.

Ayuh,..... Change the Impeller,+ do all your Backflushing at that time....

 

[WOJO 1]

Re: Back flush from raw pump

OK, thanks I'll change the impeller. Do you think garden hose pressure would be sufficient for back flushing or is that to much pressure? Not enough?

 

[Bondo]

Re: Back flush from raw pump

Ayuh,... It'll be just Fine.....

It shouldn't really take much of any Pressure,... It should All be Free Flowing....

 

[HT32BSX115]

Re: Back flush from raw pump

Can you back flush from the raw water pump out through the lower end of a Cobra SX?

Howdy,


Since this is an SX, the RAW pump is on the engine right?

Yes you can use your water hose to "backflush" if you like. It's not a bad idea. Most of the time, the blockage is due to previous impeller failures where pump fragments end up in the oil/power steering cooler(s) etc. ("backflushing" from the pump -BACK to the drive won't get that stuff out)

If you have a closed cooling system you may also have fragments or other debris in the heat exchanger.

Finally, if your risers are getting really hot (due to low flow) you may (also) have plugged (with rust) exhaust manifolds and/or risers


regards,


Rick

 

[WOJO 1]

Re: Back flush from raw pump

Thanks guys for the help.

 

[bruceb58]

Re: Back flush from raw pump

If all of this doesn't work, it may be possible that you have an air leak somewhere. Did you replace the weird looking o-ring when you replace your drive after pulling it?

Might want to do the test where you put in a clear piece of hose at the inlet of your pump and look for air bubbles.

 

[WOJO 1]

Re: Back flush from raw pump

O-Ring? Come to think of it I do not remember seeing an O-Ring. Rut-Roh.
I guess I should check the manual. I do have a spare impeller, I will have to look and see if that package has an O-Ring in it. If it ain't one thing it's a hundered.

 

[HT32BSX115]

Re: Back flush from raw pump

All it takes is a little leak above the waterline prior to inlet of (or at) the raw pump, sucking air to cause this and you could end up with more air than water making it to your cooling system.

Connecting a clear hose in the suction line or even the discharge line from the pump will reveal bubbles if that's happening...

 

[bruceb58]

Re: Back flush from raw pump

O-Ring? Come to think of it I do not remember seeing an O-Ring. Rut-Roh.
I guess I should check the manual. I do have a spare impeller, I will have to look and see if that package has an O-Ring in it. If it ain't one thing it's a hundered.

This one

Volvo part# 3852560

http://www.dougrussell.com/partscat...,2860,2859,2855,2852,2848,2863,2537,2533,2528
# 83 in this picture

 

[WOJO 1]

Re: Back flush from raw pump

I thought you guys were talking about an O-Ring for the impeller pump. That O-Ring looks like it goes in the transom? Is there a pump there as well that I need to look at?

 

[bruceb58]

Re: Back flush from raw pump

no but if your drive was off and this wasn't replaced, you could suck air which would cause your engine mounted pump to not work well.

 

[WOJO 1]

Re: Back flush from raw pump

The drive was off when the new motor went in about 2 years ago done by the boat dealer but this problem is recent.
You guys seem to know your cr@p about these boats so I will probably start a new thread with other questions after I get this problem worked out. Thanks again for all the help.