Replacement cover for impeller pump

[Angele]

For the first time on Saturday I had to change my raw water impeller whilst on the move. Turned the engine on just in readiness for dropping the mainsail and noticed the engine pitch was different and there was no water coming out of the exhaust. So, after bearing away onto a safe course, I dived below and quickly identified the problem as the impeller (missing two blades) and replaced it. Things back to normal within 10 minutes.

However, I noticed a couple of things.

Firstly, my impeller cover is somewhat salt corroded and this means the screws are difficult to remove. Indeed, one sheared immediately I applied pressure to it.

Secondly, there was only a slight sea running. Undertaking that task (and, in particular, removing the screws) in any kind of big sea would be quite an effort. (OK, so one might argue that if there was a big sea, there would probably be enough wind to allow you to sail somewhere calm before effecting the repairs).

Now, I recall seeing a new gear test on replacement pump covers in one of the yottie mags some years ago. These had thumbscrews to make removal easy.

My questions are:

Who makes them?
Are they any good?
Would you recommend them?

 

[sailorman]

For the first time on Saturday I had to change my raw water impeller whilst on the move. Turned the engine on just in readiness for dropping the mainsail and noticed the engine pitch was different and there was no water coming out of the exhaust. So, after bearing away onto a safe course, I dived below and quickly identified the problem as the impeller (missing two blades) and replaced it. Things back to normal within 10 minutes.

However, I noticed a couple of things.

Firstly, my impeller cover is somewhat salt corroded and this means the screws are difficult to remove. Indeed, one sheared immediately I applied pressure to it.

Secondly, there was only a slight sea running. Undertaking that task (and, in particular, removing the screws) in any kind of big sea would be quite an effort. (OK, so one might argue that if there was a big sea, there would probably be enough wind to allow you to sail somewhere calm before effecting the repairs).

Now, I recall seeing a new gear test on replacement pump covers in one of the yottie mags some years ago. These had thumbscrews to make removal easy.

My questions are:

Who makes them?
Are they any good?
Would you recommend them?

speedseal

 

[Angele]

That's the job. Asked at the boatshow yesterday and everyone stared at me blankly. Thought I was mad.

Any experience of using them?

 

[GrahamM376]

Speedseal http://speedseal.com/speedseal.html does what it says in the pack. Do lubricate the threads though, they can gum up and need pliers to start. You have also to be careful about locating the thin O ring properly or it leaks. Overall much quicker and easier than the small screwed covers.

 

[nigelmercier]

speedseal

I have been considering one of these, but they seem very expensive. An alternative would be to make a Teflon gasket and buy some thumbscrews, although I have not seen these in stainless steel.

 

[sailorman]

That's the job. Asked at the boatshow yesterday and everyone stared at me blankly. Thought I was mad.

Any experience of using them?

no never felt the need to have one but if i had a 1GM then certainly as the screws are very difficult to get at

 

[fisherman]

That's the job. Asked at the boatshow yesterday and everyone stared at me blankly. Thought I was mad.

Any experience of using them?

I have them, as on the tin, but you need a little more than thumbs to tighten sufficiently.

 

[Tranona]

Excellent bit of kit and worth every penny. As said really good on a Yanmar 1GM and on my current Volvo which has 6 tiny screws, one of which always ends up in the bilge. Mine are the older design without the wear plate, which seems a good addition.

 

[Angele]

I have been considering one of these, but they seem very expensive.

I had thought the same until now. However, having replaced an impeller for the first time whilst on the move (and reliant on crew keeping the boat safe in the meantime in the busy Solent), I can see that anything that minimises time spent effecting repairs is a good thing!

 

[ChattingLil]

I also have the one with the teflon inner plate. Fantastic. Easy to get on and off (and coming from me, that's saying something). And I have had to do it at sea a couple of times. Well worth the money.

 

[Angele]

Fisherman, Tranona and ChattingLil

Thanks for the feedback on use of the Speedseal. (Mine is the same as Tranona's Volvo with those tiny screws, one of which is now broken).

Am I right that the "o" ring is designed to last several seasons and you can forget about the paper gaskets in future?

 

[sailorman]

Fisherman, Tranona and ChattingLil

Thanks for the feedback on use of the Speedseal. (Mine is the same as Tranona's Volvo with those tiny screws, one of which is now broken).

Am I right that the "o" ring is designed to last several seasons and you can forget about the paper gaskets in future?

no gasket req

 

[Tranona]

Yes. Make sure you clean the face of the pump before you fit it and grease the O ring. You will get spare O rings and grease with the plate, and a tool for getting the impeller out.

 

[kieronriley]

missing blades

did you find the two missing blades from the impeller,if you didnt find and remove them your next job could be a new cylinder head gasket as they will eventualy find a small gap to stop them traveling any further around your cooling system thus reducing or stopping your water circulation,resulting in some sort of engine damage(usualy head damage)best of luck.Kieron

 

[Angele]

did you find the two missing blades from the impeller,if you didnt find and remove them your next job could be a new cylinder head gasket as they will eventualy find a small gap to stop them traveling any further around your cooling system thus reducing or stopping your water circulation,resulting in some sort of engine damage(usualy head damage)best of luck.Kieron

Yes, I'm aware of that. The repair at sea was a "get me home" job. I didn't have time to take the engine apart when I got back to my berth. But I did disable the engine to force myself to do that before my next trip out.

Where is the first place to look?

Immediately downstream from the pump is an anti-syphpon valve. That then leads to one end of the cylinder head before coming out of the other and into the exhaust system.

I'm assuming it is most likely I'll find the bits at the cylinder head (upstream side). What do you think?

 

[nigelmercier]

did you find the two missing blades from the impeller...

Would back-flushing be a good way to remove these?

 

[Norman_E]

I have seen an engine repair man get bits of impeller out of the cooling system by connecting a hose pipe to the outlet and a drain hose to the inlet and flushing the heat exchanger with mains water (it was an indirect cooled engine). The drain hose was led to a bucket so that the pieces could be seen, and the missing bits accounted for. On a direct cooled engine the same trick might be worth a try before starting to dismantle.

EDIT. The problem with direct cooled engines is that once the bits of rubber get inside the engine cooling system there are lots of places they can lodge and back flushing may not remove them. The best hope is that they have lodged in the pipe on the way in. I wonder why engines rarely seem to have a coarse stainless mesh filter between impeller and engine block. Provided such a filter was considerably coarser mesh than the sea water strainer it would not clog, but would catch impeller pieces.

 

[fisherman]

Would back-flushing be a good way to remove these?

Absolutely, in my case I used the deckwash but with a bit of flexible hose you can redirect the flow.

 

[Angele]

Nigel and Norman

Thanks for the suggestion. It is certainly worth a try.

(Mine is indirect).

Edit: and Fisherman too.

 

[Heckler]

Nigel and Norman

Thanks for the suggestion. It is certainly worth a try.

(Mine is indirect).

Edit: and Fisherman too.

Speedseal, best thing since sliced bread as others have said. The one with the teflon plate is the3 best, the teflon wears instead of the face.
Stu