Penta D1-30 Sea Water Pump Problem

[bobgarrett]

Since relaunch this year I have had problems with the sea water pump on the D1-30 engine. Sometimes water flows through to the exhaust, and once it has started it continues. But sometimes when starting the engine nothing comes through though it sometimes produces a trickle if I rev the engine. Then a bit later start the engine and it is fine.
I had thought it might be an air leak resulting in the pump not always priming but I have now replaced all the hoses and also serviced the pump with new shaft and seals etc. But the problem is still there.
I have no sea water filter and have checked the heat exchanger for blockages. I don't think there is a
I am now suspecting that maybe the impeller cover is too worn so the impeller does not make a good consistent seal.
Is that possible, have others had to replace the cover for this reason? Or could there be some other problem?

Thank you for any suggestions.

 

[scottie]

Try turning the cover outer face to impeller if you feel that

 

[Baggywrinkle]

External weed fouling that is sometimes sucked in and blocks the raw water intake, sometimes it doesn't?

 

[bobgarrett]

External weed fouling that is sometimes sucked in and blocks the raw water intake, sometimes it doesn't?

Yes, it's generally a possibility but I think sail drives are less prone to this and since it happened immediately after relaunch with a really clean bottom this seems unlikely. Thanks, though.

 

[RichardS]

Since relaunch this year I have had problems with the sea water pump on the D1-30 engine. Sometimes water flows through to the exhaust, and once it has started it continues. But sometimes when starting the engine nothing comes through though it sometimes produces a trickle if I rev the engine. Then a bit later start the engine and it is fine.
I had thought it might be an air leak resulting in the pump not always priming but I have now replaced all the hoses and also serviced the pump with new shaft and seals etc. But the problem is still there.
I have no sea water filter and have checked the heat exchanger for blockages. I don't think there is a
I am now suspecting that maybe the impeller cover is too worn so the impeller does not make a good consistent seal.
Is that possible, have others had to replace the cover for this reason? Or could there be some other problem?

Thank you for any suggestions.

The simplest thing to do is to put plenty of vaseline or silicon grease or glycerine on the impeller, pump lobes and inner surfaces and on the inner face of the outer cover and then reassemble and start the engine. If the exhaust water starts to appear after 10 or 15 seconds then you know exactly where the problem lies, although the grease will probably see you through several months of use even if you do nothing further.

Richard

 

[Easticks28]

The lubricant supplied in the sachet with a new impeller is remarkably similar to KY jelly.
Tastes similar too.....

 

[RichardS]

The lubricant supplied in the sachet with a new impeller is remarkably similar to KY jelly.
Tastes similar too.....

I think that KY Jelly is glycerine which I think is the same as glycerol so it is indeed identical to the sachet stuff. However, it is not nearly as good as an impeller pump lubricant as silicone grease. However, compared to silicone grease it has one towering advantage which is extremely attractive to manufacturers.

Richard

 

[bobgarrett]

I think that KY Jelly is glycerine which I think is the same as glycerol so it is indeed identical to the sachet stuff. However, it is not nearly as good as an impeller pump lubricant as silicone grease. However, compared to silicone grease it has one towering advantage which is extremely attractive to manufacturers.

Richard

.
Thanks for that. I did use the lubricant when fitting the impeller on relaunch. While sitting still in the crane straps the engine fired up and plenty of water came out of the exhaust. 30mins later when we went to move no water came out of the exhaust! And it has been on and off like that since.
I don't want to have to take the impeller out to lubricate it everytime I start the engine! I also thought the point of the lubricant was to reduce wear on the blades when it was dry - which it should not be later.
Thanks.

 

[Quandary]

On my relatively new D1-30 I had a chronic problem with the shaft seals which meant removing the pump several times before it was resolved, not sure if it would contribute to your problem without leaking copiously though.

 

[RichardS]

I don't want to have to take the impeller out to lubricate it everytime I start the engine! I also thought the point of the lubricant was to reduce wear on the blades when it was dry - which it should not be later.
Thanks.

I understand that completely. However, the point is that if you lubricate the pump and it then works fine for a while, the problem is with the impeller not sealing sufficiently against the housing or some other air ingress into the pump itself.

Richard