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marji

Jabsco Water Pumps Recon Project

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I want to get better at recondition, I beleave in hands on experience so I bought three water pumps from ebay, I have two here and a third one coming, I got these two for £20.  

 

I will update the thread with the stages of the recondition, but remember I am new to this I don't expect to get everything right so feel free to correct me as the thread progresses, also allow for a delay as I am going to focus on my boat Wednesday.

 

 

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1 hour ago, ditchcrawler said:

Pity these are not still available 

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At Least I know what to look for so it all helps, thanks.

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52 minutes ago, Tracy D'arth said:

By Heck! Th'a likes a challenge dun't thee?

TD'

Hi Tracy it gets even better, the third pump is the "treasure" but have not received it yet.

 

I will do a strip down and recondition once my boat is fixed, and video it for reference. I will learn by hands on experience and being corrected, by you all. :cheers:

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Pump number 3 Jabsco model 4900-200, I now have the spare I wanted for my boat.

 

 

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Bingo!  Well done.

You do realise that now you are the forum expert on Jabsco 4900-200 pumps and you will have to answer all the questions?

 

 

You are enjoying this aren't you?

Edited by Tracy D'arth
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2 hours ago, Tracy D'arth said:

Bingo!  Well done.

You do realise that now you are the forum expert on Jabsco 4900-200 pumps and you will have to answer all the questions?

 

 

You are enjoying this aren't you?

Well I am sure I am at the stage of offering basic help, still lots to learn about these pumps, Tony has said some things I need to understand better.

 

I am enjoying it yes and very happy to have got hold of this 3rd pump, I want to open the front plate to see how worn it is, and check the impeller, but waiting to make a video doing that, which I might do today.

 

 

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48 minutes ago, marji said:

Well I am sure I am at the stage of offering basic help, still lots to learn about these pumps, Tony has said some things I need to understand better.

 

I am enjoying it yes and very happy to have got hold of this 3rd pump, I want to open the front plate to see how worn it is, and check the impeller, but waiting to make a video doing that, which I might do today.

 

 

Please just ask about anything you don't understand. that way you will learn. Luckily your pump is probably the simplest type to learn on, no seals, no wear plate and no bearings.

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Thanks Tony, I am going to need advice about the shaft and pulley side of the pumps, and packing the gland, I did not ask you yet as I wanted to get a chance to open and mess about with that side of the pump, this I could not do due to leaving all my spanners on my boat while fixing the main pump at home, so I could not remove the shaft and learn, it is still a closed book, now I have an identical pump, I can now open it and get the picture in my head of the basic's, then I will be able to focus my question to you in such a way that I would understand your answer better, I am a slow learner because I feel I am thorough.

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1 minute ago, marji said:

Thanks Tony, I am going to need advice about the shaft and pulley side of the pumps, and packing the gland, I did not ask you yet as I wanted to get a chance to open and mess about with that side of the pump, this I could not do due to leaving all my spanners on my boat while fixing the main pump at home, so I could not remove the shaft and learn, it is still a closed book, now I have an identical pump, I can now open it and get the picture in my head of the basic's, then I will be able to focus my question to you in such a way that I would understand your answer better, I am a slow learner because I feel I am thorough.

 

OK lets deal with your new pump, I think the one on the boat will be subtly different pulley mounting wise so we can leave that for now.

 

The pulley on that pump seems to be secured by a taper lock system. If you look at it end on you can see the shaft with the key in it. Then a split "collar" that I think may be tapered on the pulley side. In the joint between the collar and pulley there are two holes that I think have allan screws in them. So to remove the pulley start by removing the allan screws. Then using a soft hammer try tapping the pulley back towards the pump. I think the pulley will move back allowing the collar to spring open so the whole lot can be removed from the shaft.

 

That will leave the key in place. I don't know if its a plain square key or half moon shaped Woodruff key so we will treat it like a woodruff key and if that does not shift it try another method. Get a Brass drift, not  a metal punch unless you want to be filing damage off the key, and a decent hammer.  Place the shaft on a fixed surface with the key uppermost. You will need help to hold it in position. I would use an  anvil, the back of an engineers vice or at a pinch a block of hard wood.

 

Place the drift vertically downwards on one extreme end of the key and strike a really good blow. I fully  expect the key to partially revolve in the shaft so you can pull/lever it out. If after three good blows it refuses to move then its probably a square key so :

 

Take the backplate off and stand the pump on the back face, on a solid surface with a hole in it for the protruding bit of shaft, with the key pointing upwards. Now you need help to hold the pump in place. Get a small cold chisel and put it on the end of the key right where it goes into the shaft and strike maybe three blows vertically downwards to dent the end of the key. Now angle the chisel so when you hit it the force tries to lift the key from the shaft. Hopefully another good blow will lift the key out of slot in the shaft

 

Once the pulley key is out you can draw the whole  shaft out from the back of the pump and then  remove the impellor key.

 

WARNING - I may be completely wrong about that key. It might be a taper key that has been  driven into the slot in the collar against a flat on the shaft. I rather hope it is because you will need that flat for your pulley. If it is I doubt you  could get a punch onto the back of the pulley to push the key forward but hopefully taking those screws out will allow the pulley and collar to come off. If it does not then you need a different approach and this will help you get the shaft out of your pump.

 

Remove the end cover and impellor to expose the key and push the shaft back to give you as much access to the key as possible. It will be a Woodruff so remove it as described above. you can then pull the shaft and pulley out to the front so you can get at the back of the pulley to punch the key out.

 

 If the shaft is worn you may have to loosen the gland nut to allow it to slide out.

 

 

 

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Brass Punch Pin Drive Set on order, I'll start the first part of the strip down tomorrow.

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Taper Lock System.

There will be 3 holes, 2 will/should have grub screws, to be fully removed with a Allen key.

The 3rd (middle hole) is for removal. Screw 1 of the grub screws into the 3rd hole, this will push apart the 2 sections of the Taper Lock.

The 3rd removal screw is often hard to screw in, making the whole thing come apart with quite a bang!

Reassembly, all 3 holes only line up 1 way, refit the grub screws opposite each other.  Leaving the 3rd middle hole empty.

 

Bod.

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Parts for the 4900 are starting to become hard to get.

 

I reconditioned two for my own boat last (the first one lasted over 40 years, so I reckon two should see me out...) but in both cases the shafts were worn, and they are no longer available as a spare from Jabsco so we machined some up.

 

They have a carbon ring rather than conventional packing in the gland - that was still available last time I checked.

 

Early versions of the pump have replaceable bronze bushes in the end plate and main body for the shaft and a brass wear disc behind the impeller, so as long as you know someone with a lathe they are repairable almost infinitely. Later ones don't have the bushes - but can always be bored out and have them fitted.

 

Watch out for cracking on the inside face of the endplate - I think they suffer from it if they've been run dry and got too hot.

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On 31/07/2020 at 22:31, Bod said:

Taper Lock System.

There will be 3 holes, 2 will/should have grub screws, to be fully removed with a Allen key.

The 3rd (middle hole) is for removal. Screw 1 of the grub screws into the 3rd hole, this will push apart the 2 sections of the Taper Lock.

The 3rd removal screw is often hard to screw in, making the whole thing come apart with quite a bang!

Reassembly, all 3 holes only line up 1 way, refit the grub screws opposite each other.  Leaving the 3rd middle hole empty.

 

Bod.

Thanks Bod I appreciate the information.

On 31/07/2020 at 22:48, Rose Narrowboats said:

Parts for the 4900 are starting to become hard to get.

 

I reconditioned two for my own boat last (the first one lasted over 40 years, so I reckon two should see me out...) but in both cases the shafts were worn, and they are no longer available as a spare from Jabsco so we machined some up.

 

They have a carbon ring rather than conventional packing in the gland - that was still available last time I checked.

 

Early versions of the pump have replaceable bronze bushes in the end plate and main body for the shaft and a brass wear disc behind the impeller, so as long as you know someone with a lathe they are repairable almost infinitely. Later ones don't have the bushes - but can always be bored out and have them fitted.

 

Watch out for cracking on the inside face of the endplate - I think they suffer from it if they've been run dry and got too hot.

The two reasons that I am buying pumps is one to learn and two to source the parts, that said the asap have two shafts in stock for around £80, I am thinking maybe I should buy one.

 

Thanks for the information.

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