My mysterious cooling pump

[Onedayshellbedone...]

Hi everyone, a forum newbie here looking for some help in identifying a raw water cooling pump - how hard could that be rigtht?!

But first, a little context:

I picked up a 1978 Golden Hind 31 several months ago with the intention of fixing her up as a sailing liveaboard. I had been working my way through the extensive (massive) backlog of maintenance issues, from structural to electrical when, after a few months, i finally got to the engine (seemed fitting that this should come last on a sailboat!). It's the original Lister STW2 - old and very unloved, but despite the odds being stacked against her with neglect, salt and age, she starts first time and sounds like the finest of tractors! It's a lovely engine in a lovely boat ....but......my Lister has a cooling problem - low water flow through the wet exhaust. With some help from a friendly marine engineer, the problem was in large part narrowed down to the raw water cooling pump. Given that i had already replaced the impeller, the first suspect i have is the cam, which i am now looking to replace (restrictions on the inflow and outflow have been ruled out).

My peculiar problem:

There are no identifying marks on the raw water pump body or cover plate, and it is not the original pump for this engine. The original was mounted on the crankcase and driven by a spindle from the engine, but this pump was mounted externally on a bracket and powered by the auxiliary v-belt. Without knowing the model of the pump, or even the manufacturer, i cannot get a new cam! I have contacted those i consider most likely to recognise the pump - Lister Petter's appointed supplier (Sleeman & Hawken), Jabsco's UK importer (Xylem) and ASAP Supplies, but none have ever seen this pump before. I don't think it is a Johnson or Sherwood pump, but could be wrong...

I've added links to a few pictures of the pump after removal, with the cover off...if anyone recognises it, or even if anyone wants to take a guess/make some suggestions as to its origins, it would all be helpful!

 

[Onedayshellbedone...]

Anyone..?

 

[30boat]

You may have to adapt another model.ASAP supplies perhaps?
http://www.asap-supplies.com/marine...absco-pulley-driven-engine-cooling-pump-cw403

 

[RichardS]

I'll have a go.

The cam doesn't look too bad to me but that's quite a small pump so it won't pump a lot of water. Is the engine actually overheating? Perhaps it's doing enough?

How did you replace the impeller with the correct size if you don't know the pump model? Are you sure that the impeller is the correct size? Was it so difficult to get the vanes to bend sufficiently to get it in that you have to resort to a cable tie to squish the vanes? If not, you might have vanes that are a little too short which will seriously affect the pump's displacement.

Richard

 

[sailorman]

http://www.jabscoshop.com/marine/pu...dapter-to-fit-in-place-of-22960-1001-pump.htm

http://www.jabscoshop.com/marine/pu...crankshaft-mounted-with-25mm-1-hose-ports.htm


http://www.pumpvendor.com/jabsco_parts_lists.html

http://www.pumpvendor.com/johnson_flexible_impeller_pumps.html

 

[Onedayshellbedone...]

You may have to adapt another model.ASAP supplies perhaps?
http://www.asap-supplies.com/marine...absco-pulley-driven-engine-cooling-pump-cw403

Hi 30boat, that is a possibility i may face later - find a pump of the right capacity and set it up to get the right rpm. Hoping it won't come to that as even the cheapest of these bronze pumps is 150 pounds + adapting pulleys of the right size etc. i was given an estimate in the 500-600 pound mark for an orignial pump and spindle!

 

[Onedayshellbedone...]

I'll have a go.

The cam doesn't look too bad to me but that's quite a small pump so it won't pump a lot of water. Is the engine actually overheating? Perhaps it's doing enough?

How did you replace the impeller with the correct size if you don't know the pump model? Are you sure that the impeller is the correct size? Was it so difficult to get the vanes to bend sufficiently to get it in that you have to resort to a cable tie to squish the vanes? If not, you might have vanes that are a little too short which will seriously affect the pump's displacement.

Richard

You raise some good points and questions. The engine was getting quite hot and not much water was coming out when revving, but seemed adequate when idling - it seemed to put out roughly the same amount whatever the rpm. This was confirmed when we first checked the pump intake allowed free flow of water, then varied revs with the pump outflow disconnected while watching - it just didn't vary much at all! This seems like improper operation of the pump rather than a pump size issue i think.
The impeller size...well i replaced like for like, but that doesn't mean that the impeller installed before was the right one i suppose...

Here's a pic i took with the new impeller inserted. It looks right to me, with compression at the ends of all vanes, but as robust as i hear these pumps are, i can imagine it wouldn't take much wear to reduce efficiency? I'll find out if there are any impellers the same size, but with differing numbers of vanes/types of vanes. Thanks for the thoughts!

 

[Onedayshellbedone...]

http://www.jabscoshop.com/marine/pu...dapter-to-fit-in-place-of-22960-1001-pump.htm

http://www.jabscoshop.com/marine/pu...crankshaft-mounted-with-25mm-1-hose-ports.htm


http://www.pumpvendor.com/jabsco_parts_lists.html

http://www.pumpvendor.com/johnson_flexible_impeller_pumps.html

Yeah, i have been around the block on the internet looking at jabsco, sherwood, johnson pumps. Closest match i found was:

http://www.xylemflowcontrol.com/marine-and-rv/jabsco-pedestal-pumps/2620-series-2620-38-bronze-pedestal-pump.htm

I was talking to someone from Jabsco about the similarity, but they insisted there was no relationship to any pump they ever made...on with the hunt! Thanks for the suggestions though Sailorman

 

[William_H]

One of the traps of this kind of pump is the clearance in the body and cover and the impeller. Any clearance here allows water to bypass the vanes. It is not easy to check this clearance.
The thickness of the gasket under the cover for instance can increase clearance a lot. The clearance can result from wear of the cover or body or even the wrong impeller. I think it would be obvious if the impeller was the wrong outside diameter but thickness shou8ld also be checked.
Try clamping the cover on without a gasket and check for resistance to turning by hand. If there is clearly resistance (friction impeller to cover)(good) then the gasket a thin one should just give enough clearance.
I note that an engineer said it was a pump problem. He could have been wrong. Possible obstruction corrosion in the rest of the water system and water injection into the exhaust. good luck olewill

 

[RichardS]

One of the traps of this kind of pump is the clearance in the body and cover and the impeller. Any clearance here allows water to bypass the vanes. It is not easy to check this clearance.
The thickness of the gasket under the cover for instance can increase clearance a lot. The clearance can result from wear of the cover or body or even the wrong impeller. I think it would be obvious if the impeller was the wrong outside diameter but thickness shou8ld also be checked.
Try clamping the cover on without a gasket and check for resistance to turning by hand. If there is clearly resistance (friction impeller to cover)(good) then the gasket a thin one should just give enough clearance.
I note that an engineer said it was a pump problem. He could have been wrong. Possible obstruction corrosion in the rest of the water system and water injection into the exhaust. good luck olewill

+1

When I said "are you sure that the impeller is the correct size" in post #4 I just have added "in all dimensions".

Richard

 

[Onedayshellbedone...]

Ahhhhhhhhhhhhhhhhhh, problem solved!!!!

Thanks for all the advice guys. Turns out that it's not a problem with the pump innards - had been tinkering with the impeller, sanding off a protrusion (that resulted from a poor mould i think) and thought i'd reassemble and test with a cordless drill. It worked fine, so 'problem solved!'....i thought...reinstall pump, fire up engine...same problem . Then i got a light wiff of burning rubber....put 2 and 2 together and turns out the problem was with the v-belt!!!! I had tensioned it correctly when installing, but i hadn't considered that this pump was never meant to be run from the v-belt. The location that it had been placed meant that it did not wrap around the crankshaft pulley properly, but makes an angle of <90 degrees around it. The crankshaft pulley was slipping at higher revs, resulting in the alternator and water pump not revving with it and no change in water flow out of the transom at different rpm's!!! When i tensioned it up further, water flow became proportional to rpm's. So this solves one problem, but presents another - there's probably too much tension in the belt now...i see damaged alternator and water pump bearings in my future with this setup...

So in summary:

1) cause of poor coolant flow identified as slipping v-belt caused by poor pump location (should really only be two pulleys per belt i think)

2) the pump manufacturer is still a mystery, but this seems less of a priority now

3) i think i'll keep hunting for an orignial spindle driven water pump!!!

Thanks all

 

[30boat]

Ahhhhhhhhhhhhhhhhhh, problem solved!!!!

Thanks for all the advice guys. Turns out that it's not a problem with the pump innards - had been tinkering with the impeller, sanding off a protrusion (that resulted from a poor mould i think) and thought i'd reassemble and test with a cordless drill. It worked fine, so 'problem solved!'....i thought...reinstall pump, fire up engine...same problem . Then i got a light wiff of burning rubber....put 2 and 2 together and turns out the problem was with the v-belt!!!! I had tensioned it correctly when installing, but i hadn't considered that this pump was never meant to be run from the v-belt. The location that it had been placed meant that it did not wrap around the crankshaft pulley properly, but makes an angle of <90 degrees around it. The crankshaft pulley was slipping at higher revs, resulting in the alternator and water pump not revving with it and no change in water flow out of the transom at different rpm's!!! When i tensioned it up further, water flow became proportional to rpm's. So this solves one problem, but presents another - there's probably too much tension in the belt now...i see damaged alternator and water pump bearings in my future with this setup...

So in summary:

1) cause of poor coolant flow identified as slipping v-belt caused by poor pump location (should really only be two pulleys per belt i think)

2) the pump manufacturer is still a mystery, but this seems less of a priority now

3) i think i'll keep hunting for an orignial spindle driven water pump!!!

Thanks all

Or you could make or adapt a ballbearing tensioner to wrap the belt further around the pulley.An adjustable arm with a cambelt roller or something.Too much tension will wreck the bearings on the pump,alternator and perhaps the crankshaft.

 

[Onedayshellbedone...]

Or you could make or adapt a ballbearing tensioner to wrap the belt further around the pulley.An adjustable arm with a cambelt roller or something.Too much tension will wreck the bearings on the pump,alternator and perhaps the crankshaft.

yeah, i've been thinking about that. difficult to place one where it would need to be unfortunately. I replaced the belt and seem to be able to have the tension a little lower without it slipping....still a little too much i think, but not ridiculous. Will prob leave as is and keep an eye out for an original pump going cheap :nonchalance: