Raw water pump

[Jeffrey52]

Hi, I have a 1500 BMC engine and the raw water pump as jammed, I stripped out the impeller and it is still very stiff to turn, Any suggestions would be greatly appreciated.

[Tony Brooks]

There have been many raw water pumps fitted to 1.5 BMCs so a photo may help identify the pump. I suspect this is a heat exchanger system with a pump shaft supported on ball bearings. If so a seal has probably failed and the bearings have rusted up. Fitting new bearings and seal will probably be way cheaper than another pump. Take the old ones to Brummer or Bearing Boys etc. who will probably pattern them up for you.

 

If it is not a ball bearing pump then it can only be the shaft seized in the body or shaft seal packing jammed between shaft and pump body, probably because of excess wear.

[Opener]

OK - probably totally irrelevant but is the shaft on bearings (Tony, above) or a sliding fit?  I had an issue with a kitchen tap and bush (at home) which seemed to be seized solid due to hard water.  The supplier was out of stock but suggested soaking in vinegar for an hour - worked a treat.  May be worth a try if other solutions (oops!) don't work.

[Tony Brooks]

27 minutes ago, Opener said:

OK - probably totally irrelevant but is the shaft on bearings (Tony, above) or a sliding fit?  I had an issue with a kitchen tap and bush (at home) which seemed to be seized solid due to hard water.  The supplier was out of stock but suggested soaking in vinegar for an hour - worked a treat.  May be worth a try if other solutions (oops!) don't work.

How do you expect anyone to know that for certain? I told you "There have been many raw water pumps fitted to 1.5 BMCs so a photo may help identify the pump" and I have not seen a photo or any other form of pump identification.

 

There is also a question over the type of seals the pump uses. Most use lips seals nowadays but in the past some used carbon ring seals. We do not know for certain if this is a dry or wet exhaust boat, direct raw water or heat exchanger cooled, or even a direct raw water system using a skin tank instead of canal water.

 

Typically but not for certain the bearings are a light press/drift fit in the body and the shaft is a light press fit in the bearing(s) but until the pump is identified  there may be no bearings at all apart from the shaft running in the brass pump body. That type of pump usually has a grease cap on it.

 

People who want help really should be willing to meet us halfway and give us what information they can when asked questions to clarify the situation.

 

[Sea Dog]

7 minutes ago, Tony Brooks said:

How do you expect anyone to know that for certain? I told you "There have been many raw water pumps fitted to 1.5 BMCs so a photo may help identify the pump" and I have not seen a photo or any other form of pump identification.

 

There is also a question over the type of seals the pump uses. Most use lips seals nowadays but in the past some used carbon ring seals. We do not know for certain if this is a dry or wet exhaust boat, direct raw water or heat exchanger cooled, or even a direct raw water system using a skin tank instead of canal water.

 

Typically but not for certain the bearings are a light press/drift fit in the body and the shaft is a light press fit in the bearing(s) but until the pump is identified  there may be no bearings at all apart from the shaft running in the brass pump body. That type of pump usually has a grease cap on it.

 

People who want help really should be willing to meet us halfway and give us what information they can when asked questions to clarify the situation.

 

I think, having read it twice, this broadly translates as "Why you no flukken rissen, cooky boy?"

 

(Who was it said that? Benny Hill?)

[WotEver]

1 hour ago, Sea Dog said:

Who was it said that? Benny Hill?

Probably. I can hear it being said but can’t put a face to it. 

[Jeffrey52]

Sorry cant upload pics. Its a raw water pump that draws water from from outside the boat and it feeds a bullman and then mixes with the exhaust emissions. It is a Jabsco.

It also has two greasing points either side, I have cleaned these and filled with fresh grease and the pump has become more easier to turn but not exactly spinning.

[Tony Brooks]

1 hour ago, Jeffrey52 said:

Sorry cant upload pics. Its a raw water pump that draws water from from outside the boat and it feeds a bullman and then mixes with the exhaust emissions. It is a Jabsco.

It also has two greasing points either side, I have cleaned these and filled with fresh grease and the pump has become more easier to turn but not exactly spinning.

I think I know the pump, I take it by grease points you actually mean grease caps that you unscrew, fill  the cap with grease, and the screw the cap back on and tighten  to force grease into the bearings. I believe it to be obsolete so the Jabsco shop can probably advise on a suitable replacement.

 

I THINK that pump is foot mounted, pulley driven, and has the shaft running in the cast brass pump body so once the impeller is out the shaft should spin freely. I also think there may be a large hexagon nut behind the pulley around the shaft. If so that contains gland packing to seal the shaft. This may have been overtightened or the body so worn packing has been forced between shaft and body.

 

From memory the impeller is driven by a key in the shaft so to strip you take the end cover off (6 screws), pull  the impeller out, remove the key, and then you should be able to pull the shaft out of the pump by the pulley. If it is really tight undo the big hexagon nut and tap the shaft out using a wooden mallet or a plastic/hide/soft hammer.

 

The image below is, I think, your pump's little cousin and was used on keel cooled 1.5s. The major difference apart from size is the position of the inlet and outlet plus instead of a plain flat backplate yours has a casting to carry the end of the shaft plus another grease cap. You can see the hexagon nut I referred to above in the image.

 

 

 

That is all I can say at present except to tell you I simply copied and pasted the image into my message.

 

 

 

[Jeffrey52]

That's virtually the same but mine has a screwable grease point in front of the impellar unit as well. I have tried to undo the larg nut but it's solid. Thanks for reply and all your help. It's much appreciated, I will continue to try to loosen the nut and order a new impeller, Thanks again.

[Tony Brooks]

The large nut should have a thin lock nut behind it. Normally you loosen the thin nut and then the large nut simply unscrews but my guess is that over the years the locknut has bee screwed tight back against the end of the threads and the  big nut tightened down on it. I think it is now a two person job.

 

Get a strong open ended spanner that correctly fits the lock nut in a vice held very tight by the edges. Get someone to hold the pump  with the locknut in the jaws of the spanner. Then get another spanner on the big nut to undo it. Although gross bad practice I fear you may  have to find a way of extending the spanner on the big nut. I usually hook a ring spanner onto the end of an open ended one.

 

If you get it off try to order a new packing. if none are available you might have to flatten a piece of the thinnest stern gland packing you can get. The packing goes into the big nut from memory without any gaps at the ends of the packing.  When you tighten the big nut only tighten it until you can feel a little resistance to turning the shaft without the impeller in palace, you can always tighten it a little later if it leaks or sucks are and refuses to prime without revving the engine. Then tighten the locknut against the big nut.  There should be thread showing on the pump body but at present I doubt any is on yours.

[Jeffrey52]

I have managed to loosen the hexagon nut and it is now turning much better.

[Jeffrey52]

Do I need to do anything to the shaft before replacing the packing and the nut. The pump you have pictured is the tempory replacement I have at the moment but not enough water is getting through.

 

Edited March 9, 2019 by Jeffrey52

[ditchcrawler]

Seen this on ebay https://www.ebay.co.uk/itm/Raw-water-pump-With-brass-impellers/333080860772?hash=item4d8d2a9864:g:4-YAAOSw3AFcaved

[Jeffrey52]

Just sptted another one on the Ebay link for £80 and it's exactly the same as mine. If I cant fix mine I will have to dig deep and swallow my sorrow, LOL.

 

[Tony Brooks]

33 minutes ago, ditchcrawler said:

Seen this on ebay https://www.ebay.co.uk/itm/Raw-water-pump-With-brass-impellers/333080860772?hash=item4d8d2a9864:g:4-YAAOSw3AFcaved

That looks like a gear pump so have my doubts if it will self prime with water unless it and all parts of the suction pipe is below the water line.

 

[Tony Brooks]

39 minutes ago, Jeffrey52 said:

Do I need to do anything to the shaft before replacing the packing and the nut. The pump you have pictured is the tempory replacement I have at the moment but not enough water is getting through.

 

Personally I would take it out (as described earlier) so I could inspect it for wear and remove and pieces of packing that may have found their way into the bearing. Then inspect the holes in the body for shape. I suspect that you will find it is egg shaped or oval. If so it is likely to suck air down the shaft rather than water and not prime unless you use the grease cap to temporarily seal the gap with grease. If the shaft and body look OK put the shaft in the pump body and rock it from side to side. There should be all but zero play.

 

If the pump body id worn then Richard (RLWP) might be able to sleeve it for you and even make a new shaft.

 

Of course that little pump is too small. It was never used on a heat exchanger engine, only keel cooled engines with wet exhausts to supply the exhaust cooling water. I think the small one has a 3/8" or 1/2" wide impeller while yours used a larger diameter impeller that is 3/4" or 1" .

 

Be very wary of Ebay second hand pumps. If yours is worn so it won't prime there is a good chance the Ebay one will be as well.

[Tony Brooks]

Further thoughts.

I have a feeling that you may need to pull the shaft backwards so you can remove the key before you can get the impeller out. If so you may well find the pulley prevents this. I think it was made that way so the impeller preventing the shaft working itself forwards out of the pump  allowing the key to damage the pump body. On the hire fleet I seem to recall that upon reassembly we changed that about so we could easily get the impeller out "up river" but then teh shaft would not fit fully home in the back cover  bearing and the pulley had to be repositioned, it is even possible we had to file a flat on the shaft for the pulley securing bolt to bear on (can't remember all the details - 50 years ago now.

[ditchcrawler]

There are loads of drawings here, dont know if your pump is one https://www.google.com/search?q=jabsco+brass+brass+raw+water+pump+drawings&tbm=isch&source=iu&ictx=1&fir=Ikks_ggsuhS9jM%3A%2CdVCAQLhLzcqBkM%2C_&vet=1&usg=AI4_-kQI9x46rpLz79qxboPG05f_1YECFQ&sa=X&ved=2ahUKEwjc48jogvbgAhV-VBUIHY7rB_YQ9QEwAXoECAUQBg#imgrc=Ikks_ggsuhS9jM:

[Tony Brooks]

 

I think this is the one the OP has and suspect its been out of production for 30 to 40 years

[LEO]

8 hours ago, Tony Brooks said:

 

I think this is the one the OP has and suspect its been out of production for 30 to 40 years

My first boat, purchased in 1988 had a pump similar to the previous picture, I upgraded this to the model in the attached picture in 1992, to improve water circulation (it was a BMC raw water cooled engine). I got the new unit from Cleghorn & Waring? in Baldock. I replaced the screwed grease caps for grease nipples. It's probably still in use on the engine. It worked well, but you had to get the right sized Picador pulley for good circulation of the coolant. I eventually changed the engine from raw water cooling to a heat exchanger system. Sounds to me as though the OP ran into problems with his pump through a lack of grease. If adjusted correctly you will get the odd drip of water through the nut, it's best not to over tighten this.

[Tony Brooks]

41 minutes ago, LEO said:

My first boat, purchased in 1988 had a pump similar to the previous picture, I upgraded this to the model in the attached picture in 1992, to improve water circulation (it was a BMC raw water cooled engine). I got the new unit from Cleghorn & Waring? in Baldock. I replaced the screwed grease caps for grease nipples. It's probably still in use on the engine. It worked well, but you had to get the right sized Picador pulley for good circulation of the coolant. I eventually changed the engine from raw water cooling to a heat exchanger system. Sounds to me as though the OP ran into problems with his pump through a lack of grease. If adjusted correctly you will get the odd drip of water through the nut, it's best not to over tighten this.

I agree but suspect the boat may be new to the OP. The potential for lack of greasing is what makes me suspicious the body has worn badly so it sucks air down the shaft so won't prime without a load of revs. That may well have caused someone to over-tighten the gland but if so its only a very temporary cure.

 

I agree the drive belt can be run very slack and it saves on side thrust and bidy wear.

 

I think Cleghore & Wering now trade as The Jabsco Shop or have been taken over by that company.

[Jeffrey52]

That is my pump exactly Tony and it was the packing that was impeding the shaft turning, All sorted now, I also managed to aquire a brand new one, Surplus to requirements now lol.

[OldGoat]

2 hours ago, Jeffrey52 said:

That is my pump exactly Tony and it was the packing that was impeding the shaft turning, All sorted now, I also managed to aquire a brand new one, Surplus to requirements now lol.

Always handy to have a spare (provided that it didn't cost an arm and two legs)