Reduced Seawater Circulation in Volvo MD2030

[Pieter]

Greetings!
I had noticed that the volume of seawater that runs through the engine became somewhat reduced and so i checked the seawater filter (no debris) and the impeller of the water pump. Sure enough the impeller was dammaged (one blade was missing). I couldnt locate inside the pumphouse this part, and so i presume it has been pushed into the heatexchange system (or boiler).
Now, before i rip the whole water cooling system appart, does anybody now if there is an easier way of checking and trying to get this obstruction out of the system? In fact, i dont know IF such obstruction indeed excists. Maybe the part has already been blown out the exhaust. In that case I have a different problem.

Anyway, looking forward to your suggestions....

Thanks and fair winds and enough water under your keel.
Pieter Kommerij
SV Onda Boa - Brazil

[Mark Zarley]

where oh where has that little blade gone? Yes you need to find it. Go to the pump side of the heat exchanger , if not there it could be hiding in the pump outlet fitting.

[Pieter]

thanks Mark, sure will check this also... A friend of mine (building his own sailboat) is going for electrical motors (AMSO - Denmark), and he has me almost conviced.....

Best rgds
Pieter

[never monday]

Originally Posted by Mark Zarley

where oh where has that little blade gone? Yes you need to find it. Go to the pump side of the heat exchanger , if not there it could be hiding in the pump outlet fitting.

they can also lodge in the pump inlet

[colemj]

Broken vanes on our 2030 always go to the raw water side of the heat exchanger. I have always been able to retrieve them by removing the raw water hose and fishing around in the rubber heat exchanger boot with a pair of forceps.

Mark

[Surveyor]

Originally Posted by colemj

forceps

Another item to add to the tools list.

Back in the day I had these laying all over for some strange reason.

[Pieter]

To all,

Yep, found it, just as Mark (Colemj) predicted. However.....
Still not adequate amounts of seawater going through... in fact, i notice that with the motor running ( say 1.000 rpm) i notice that after the water pump seemingly air is sucked into the system. Now, i did check the hoses (in and out of the pump) and also checked and applied a second paper seal (as supplied by our friends of Volvo) closing the pump, but still the same thing: air bubbles in the whose on the outlet side of the pump... If any of you guys have an idea... pls let me know...

Thanks and have a great weekend...

Pieter

[Randyonr3]

Not say this is your problem but a friend of mine had a "Clam" growing in his inlet.. sometimes the water ran fine but at other times the clam would be sideways and block the flow.. he didnt find the problem as he only motored out of the marina and then put the sails up until he had pulled the boat and when inspecting the thru hulls, found the clam........

[Jesse]

Try disconecting the intake hose from the pump and back flushing it to remove any obstructions while carefully observing it for leaks.

[DeepFrz]

Strainer is highly suspect.

[svcattales]

Originally Posted by Pieter

To all,

Yep, found it, just as Mark (Colemj) predicted. However.....
Still not adequate amounts of seawater going through... in fact, i notice that with the motor running ( say 1.000 rpm) i notice that after the water pump seemingly air is sucked into the system. Now, i did check the hoses (in and out of the pump) and also checked and applied a second paper seal (as supplied by our friends of Volvo) closing the pump, but still the same thing: air bubbles in the whose on the outlet side of the pump... If any of you guys have an idea... pls let me know...

Thanks and have a great weekend...

Pieter

Pieter, I assume you have saildrives. Have you checked the seawater inlet holes for barnacles or other growth? The water passages inside the drive can also have growth that you can't see and can't clean. During last haulout, I installed new seacocks for each engine and capped off the inlet through the saildrives... much better water flow.

[mellorg]

I have a similar problem in that the 2030 runs with a good sea water flow for 15 minutes or so, then the flow gradually stops. I've tried to back flush any obstructions out through the saildrive. Impeller is new with no vanes missing and none ever lost previously.

Any thoughts?

[GordMay]

Greetings and welcome aboard the CF, mellorg.

[HopCar]

I vote with Deepfrz on this one. You just had the strainer open to clean it. I'd check the gasket and make sure the lid is on tight. If the pump is sucking air the flow would be reduced and there would be bubbles.

[svcattales]

Originally Posted by mellorg

I have a similar problem in that the 2030 runs with a good sea water flow for 15 minutes or so, then the flow gradually stops. I've tried to back flush any obstructions out through the saildrive. Impeller is new with no vanes missing and none ever lost previously.

Any thoughts?

Since you have good flow at start-up, I would suspect an intermittent blockage somewhere in the water intake side. Have you checked the little intake holes in the saildrive for growth? The water also goes through passages inside the saildrive and I found growth in there when I removed saildrive to replace the rubber grommet. Hopefully, that is not the cause of your flow problem.

You might try disconnecting the intake hose from the strainer and have it pour into a bucket to see if there is any restriction to flow. (make sure hose is long enough to get above your water line so you can stop it quickly by lifting the end) You could also close the seacock and remove the intake hose to see if there is any debris in the hose.

Let us know what you find in your trouble shooting.