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  1. #1

    Default Volvo Penta V8 270 - Raw water pump issues

    Wondering if anyone can provide some insight into this problem, as I feel my mechanic is not doing a very good job in dealing with the issue. I recently had my mechanic replace the raw water pump on my engine, as it was showing a small leak. After replacement, the engine started overheating the first time I took the boat out, fortunately while I was still at the dock. Mechanic came back and checked it out, and noticed that there was no suction whatsoever when placing his hand on the pump he had just replaced (after removing the hose). He claims it was a faulty pump (original Volvo Penta part) and will be replacing it with a new one.

    However, I noticed by looking at some videos, that the serpentine belt was not installed correctly. Instead of running it from the belt tensioner down to the raw water pump and back up to the circulating pump as shown in the engine diagram, he ran it from the tensioner around the circulating pump pulley and then down to the raw water pump. If my hunch is correct, this is causing the pulleys in the raw water pump as well as the circulating pump to rotate in the opposite direction of how they were designed to rotate, which is probably why there's no suction coming from that pump. UPDATE: I CHECKED A VIDEO OF MY ENGINE RUNNING AND NOTICED THAT THE PULLEYS ARE ROTATING IN THE RIGHT DIRECTION (CLOCKWISE FOR RAW WATER PUMP, COUNTERCLOCKWISE FOR CIRCULATING PUMP), DESPITE THE BELT BEING INSTALLED INCORRECTLY. NONETHELESS, I BELIEVE THIS COULD BE THE ROOT OF THE PROBLEM.

    Besides firing my mechanic, my question is whether the impellers on both of those pumps would have suffered any damage and if any other components could have been damaged in either pump. Also, any thoughts on potential engine damage from overheating would be welcome (temperature only reached about 180 degrees, warning alarm worked properly and engine was turned off after a just a few minutes).

    Thanks!
    Last edited by will_zee; 07-04-2020 at 09:07 PM.

  2. #2
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    Default Re: Volvo Penta V8 270 - Raw water pump issues

    ............
    Quote Originally Posted by will_zee View Post
    Wondering if anyone can provide some insight into this problem, as I feel my mechanic is not doing a very good job in dealing with the issue. I recently had my mechanic replace the raw water pump on my engine, as it was showing a small leak. After replacement, the engine started overheating the first time I took the boat out, fortunately while I was still at the dock. Mechanic came back and checked it out, and noticed that there was no suction whatsoever when placing his hand on the pump he had just replaced (after removing the hose). He claims it was a faulty pump (original Volvo Penta part) and will be replacing it with a new one.
    If the impeller is correct for the pump body, and if the impeller cam is OK, it should provide suction and supply seawater.

    However, I noticed by looking at some videos, that the serpentine belt was not installed correctly. Instead of running it from the belt tensioner down to the raw water pump and back up to the circulating pump as shown in the engine diagram, he ran it from the tensioner around the circulating pump pulley and then down to the raw water pump. If my hunch is correct, this is causing the pulleys in the raw water pump as well as the circulating pump to rotate in the opposite direction of how they were designed to rotate, which is probably why there's no suction coming from that pump. UPDATE: I CHECKED A VIDEO OF MY ENGINE RUNNING AND NOTICED THAT THE PULLEYS ARE ROTATING IN THE RIGHT DIRECTION (CLOCKWISE FOR RAW WATER PUMP, COUNTERCLOCKWISE FOR CIRCULATING PUMP), DESPITE THE BELT BEING INSTALLED INCORRECTLY. NONETHELESS, I BELIEVE THIS COULD BE THE ROOT OF THE PROBLEM.

    OK.... I need to stop and ask a few questions.
    Your thread title indicates Volvo Penta V8 270.
    Are you asking about the V8 270 A or V8 270 B?

    I see that this engine was available with or without a closed cooling system.

    Here is one arrangement for the V8 270 A seawater pump.
    Note that the suction and supply ports are aiming towards Starboard.





    Here is another arrangement.
    Note that the suction and supply ports are aiming towards Port.




    FYI, it is very easy to get the suction and supply hoses reversed.


    Besides firing my mechanic, my question is whether the impellers on both of those pumps would have suffered any damage and if any other components could have been damaged in either pump.
    Yes!


    Also, any thoughts on potential engine damage from overheating would be welcome (temperature only reached about 180 degrees, warning alarm worked properly and engine was turned off after a just a few minutes).
    Worst case, the interior of the exhaust couplers became blistered.
    I would pull them apart and take a look.


    Thanks!
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  3. #3

    Default Re: Volvo Penta V8 270 - Raw water pump issues

    Hi Ricardo,

    Thanks a lot for your quick response. To answer your question, my engine is a Volvo Penta V8 270-C-B. The supply and suction ports face Starboard, as in the first diagram. However, I checked the hoses to make sure they weren't reversed as you suggest, but the two hoses are actually different sizes, so they can't be installed incorrectly into the pump (you can see the size difference between the supply and intake ports in the first diagram). Do you think that having the serpentine belt installed incorrectly could be the reason the pump is not working? I mean, the replacement pump came with an impeller, so it should match the pump it came with (I hope).

    Thanks for your input!

  4. #4
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    Default Re: Volvo Penta V8 270 - Raw water pump issues

    The serpentine belt is crank shaft driven.
    The seawater pump mounts directly to the crankshaft balancer.

    The sea water pump has no choice but to turn in the correct direction.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  5. #5

    Default Re: Volvo Penta V8 270 - Raw water pump issues

    Gotcha. In that case, let's hope that replacing the pump one more time will solve the problem! I mean, the old pump was working just fine, even though it had a small leak that was causing some corrosion to other engine parts. So I assume that there's no blockage or anything else in the cooling system that would cause the pump to have no suction whatsoever. Scratching my head with this one!

    Thanks a lot for your insight Rick, I appreciate it.

  6. #6
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    Default Re: Volvo Penta V8 270 - Raw water pump issues

    Quote Originally Posted by will_zee View Post
    Volvo Penta V8 270-C-B. The supply and suction ports face Starboard, as in the first diagram.
    Will, just like shown here.


    Click image for larger version. 

Name:	Crankshaft pump for will zee.jpg 
Views:	5 
Size:	37.1 KB 
ID:	24097
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  7. #7

    Default Re: Volvo Penta V8 270 - Raw water pump issues

    Excellent, thank you. Thatís how theyíre connected, yet thereís no suction. Hopefully replacing the potentially damaged pump will take care of the issue. What are the chances of getting another new pump that doesnít work either, right? Of course, Iíll have the mechanic install the serpentine belt correctly this time.
    Quote Originally Posted by RicardoMarine View Post
    Will, just like shown here.


    Click image for larger version. 

Name:	Crankshaft pump for will zee.jpg 
Views:	5 
Size:	37.1 KB 
ID:	24097

  8. #8
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    Default Re: Volvo Penta V8 270 - Raw water pump issues

    Quote Originally Posted by will_zee View Post
    Excellent, thank you. That’s how they’re connected, yet there’s no suction. Hopefully replacing the potentially damaged pump will take care of the issue. What are the chances of getting another new pump that doesn’t work either, right? Of course, I’ll have the mechanic install the serpentine belt correctly this time.

    Inside of the pump body will be an impeller cam.
    The cam folds the impeller vanes as it rotates.
    This action creates the suction and the outgoing supply.
    ..... Vanes leaving the cam open up the area and create suction.
    ..... Vanes entering the cam, collapse and create pressure.

    Here is an updated image.

    Click image for larger version. 

Name:	Crankshaft pump for will zee.jpg 
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ID:	24110

    Is the cam OK?
    Is the cam folding the impeller vanes as each one passes over it?
    Is the impeller depth correct for the pump body's depth? (impeller should sit proud of the pump body approx .010")
    Are the two thrust surfaces OK? (the surfaces that the front and rear ends of the impeller ride against)


    These are examples only.



    Click image for larger version. 

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    Click image for larger version. 

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ID:	24109
    Last edited by RicardoMarine; 07-06-2020 at 08:42 AM.
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

  9. #9

    Default Re: Volvo Penta V8 270 - Raw water pump issues

    Thank you Rick. Iíve ordered the new pump and should receive it by Wed/Thu. Will report back by end of week to see if that solves the problem. Appreciate all the knowledge!

    Quote Originally Posted by RicardoMarine View Post
    Inside of the pump body will be an impeller cam.
    The cam folds the impeller vanes as it rotates.
    This action creates the suction and the outgoing supply.
    ..... Vanes leaving the cam open up the area and create suction.
    ..... Vanes entering the cam, collapse and create pressure.

    Here is an updated image.

    Click image for larger version. 

Name:	Crankshaft pump for will zee.jpg 
Views:	8 
Size:	62.0 KB 
ID:	24110

    Is the cam OK?
    Is the cam folding the impeller vanes as each one passes over it?
    Is the impeller depth correct for the pump body's depth? (impeller should sit proud of the pump body approx .010")
    Are the two thrust surfaces OK? (the surfaces that the front and rear ends of the impeller ride against)


    These are examples only.



    Click image for larger version. 

Name:	impeller pump designs.png 
Views:	9 
Size:	285.6 KB 
ID:	24108




    Click image for larger version. 

Name:	Seawater pumps cam vs eccentric.png 
Views:	12 
Size:	242.9 KB 
ID:	24109

  10. #10
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    Default Re: Volvo Penta V8 270 - Raw water pump issues

    FYI.... the smallest suction breach will prevent any seawater pump from pulling in water.

    You can use a shop vac on the suction hose that connects to the pump's inlet fitting, and apply shave cream (yes, believe it or not.....shave cream) at each suspect area.
    If the shave cream starts to disappear, there's your breach.


    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP drives

    "Intellectual growth should commence at birth and cease only at death." Albert Einstein

    Please... no PMs! Post your questions on the forum.

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