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jimbob01

Lister jp3 coupling

17 posts in this topic

Hi all, I have a clattery coupling on my fuel pump, I've sourced the replacement part... like a disc with slots in it made from a material Im not familiar with.

does anyone know the correct procedure for replacing the old one?

i am a bit concerned as an amateur as to weather or not the timing can be affected taking the old one off?

any help is greatly recieved 

many thanks Jim 

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I'd mark both couplings up before removing the pump so you have a sporting chance when reconnecting. It's likely the pump will spring round when removing as one of the internal springs will be against the cam lobes. 

I would also check the spill timing when you reassemble as per the workshop manual....it's worth checking the timing marks are right...my JP2 has a JP3 flywheel....when I got the boat it was running a bit lumpy...turns out the pump was timed on the flywheel marks.....

Whilst the coupling is a good place to start be warned that you might be looking at a pump overhaul to cure all the clatter. Check the oil level in the pump...often they are full of diesel from leaking elements which does the cam in the pump no good at all. 

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16 minutes ago, frangar said:

I'd mark both couplings up before removing the pump so you have a sporting chance when reconnecting. It's likely the pump will spring round when removing as one of the internal springs will be against the cam lobes. 

I would also check the spill timing when you reassemble as per the workshop manual....it's worth checking the timing marks are right...my JP2 has a JP3 flywheel....when I got the boat it was running a bit lumpy...turns out the pump was timed on the flywheel marks.....

Whilst the coupling is a good place to start be warned that you might be looking at a pump overhaul to cure all the clatter. Check the oil level in the pump...often they are full of diesel from leaking elements which does the cam in the pump no good at all. 

It's fun that 3 cylinder flywheel on a 2 cylinder engine isn't it. It took me some time with a bit of chalk to work out what marks I could rely on (number 2 from memory)

As you say, chances are you'll find the bearings have gone in the pump

Richard

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3 minutes ago, RLWP said:

It's fun that 3 cylinder flywheel on a 2 cylinder engine isn't it. It took me some time with a bit of chalk to work out what marks I could rely on (number 2 from memory)

As you say, chances are you'll find the bearings have gone in the pump

Richard

Luckily we had the heads off anyhow so were able to make new marks on the flywheel....amazingly it ran okish with some smoke...it explained being tricky to start tho....and once ran backwards after hand starting...the handle found a very unfortunate place to hit me and tried to put me out the engine room side door......

If the pump does need an overhaul it's not a cheap fix and some of the parts can be a tad tricky to get

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2 hours ago, frangar said:

I'd mark both couplings up before removing the pump so you have a sporting chance when reconnecting. It's likely the pump will spring round when removing as one of the internal springs will be against the cam lobes. 

I would also check the spill timing when you reassemble as per the workshop manual....it's worth checking the timing marks are right...my JP2 has a JP3 flywheel....when I got the boat it was running a bit lumpy...turns out the pump was timed on the flywheel marks.....

Whilst the coupling is a good place to start be warned that you might be looking at a pump overhaul to cure all the clatter. Check the oil level in the pump...often they are full of diesel from leaking elements which does the cam in the pump no good at all. 

I have been considering checking the spill timing on mine, but have found the manual confusing and it refers to a 23" flywheel (mine's 26")! Any clarification would be appreciated.

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Check to see if it is marked first

Richard

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6 hours ago, RLWP said:

Check to see if it is marked first

Richard

And look for a serial number on the edge to make sure it's the right flywheel for the engine!! 

The model is part of the serial number. 

 

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Yes, the serial numbers match and there is a mark that looks like a lightning bolt.

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2 hours ago, BWM said:

Yes, the serial numbers match and there is a mark that looks like a lightning bolt.

Oh dear,  looks like Vodemort has hexed your engine :wacko:

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I've put my finger against the coupling as it's running and the noise stops...

i was hoping the coupling was worn....

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1 hour ago, jimbob01 said:

I've put my finger against the coupling as it's running and the noise stops...

i was hoping the coupling was worn....

The coupling on mine was shot when we acquired it, should be fairly obvious if you check for movement of the fibre disc with the engine off.

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Thanks bwm...

im still not sure it's simple enough for me to tackle though .....

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It is, in fact, dead easy. The hardest part is probably accessing the bolts - which are Whitworth of course. Chances are the hardest one is missing

Put a mark across the two metal parts of the coupling, slacken or remove the fuel pipes, take out the bolts, slide the pump back. You'll probably find the pump shaft rotates  a bit until the cam followers hold the camshaft still.

Take out the old coupling, put in the new one.

Turn the engine by hand using the flywheel (and decompressors) until your marks line up and then put it all back together. If you took the pipes off, bleed the pump

You can only put this back together right, or half a revolution out - and if you mark the coupling you won't get it half a revolution out

Richard

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Posted (edited) · Report post

1 hour ago, RLWP said:

Half a pump revolution out maybe, but that is a whole flywheel revolution.  The spill timing can then look correct  to those who fail to double check what the valves are doing. DAMHILTTHW!

N

Richard did not say the above. I did

 

N

Edited by BEngo
Strange quote result.
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Thanks for that Richard... very clear, that shall be my next wet weather inside job . Jim

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I tried taking the pump off the JP2 in the tug because the coupling is worn- there are a few types and so I wanted to measure it.

Annoyingly, it is held on with studs and nuts, rather than bolts. So the nuts can be removed and all the pipes disconnected, but with the studs in place the pump can't be lifted vertically to be removed.

 

The space available is very small, for a stud remover. Access to one end is limited because of the flywheel and the body of the engine.

 

Maybe the put-two-nuts-on trick to remove the studs? Might even replace them with bolts afterwards......

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On Monday, March 20, 2017 at 21:28, FadeToScarlet said:

I tried taking the pump off the JP2 in the tug because the coupling is worn- there are a few types and so I wanted to measure it.

Annoyingly, it is held on with studs and nuts, rather than bolts. So the nuts can be removed and all the pipes disconnected, but with the studs in place the pump can't be lifted vertically to be removed.

 

The space available is very small, for a stud remover. Access to one end is limited because of the flywheel and the body of the engine.

 

Maybe the put-two-nuts-on trick to remove the studs? Might even replace them with bolts afterwards......

I'm guessing that you have undone the two nuts holding the pump bracket on rather than the four underneath the pump, I reckon it is probably easier to remove the pump this way. If you are changing the coupling you should be able to do so by just moving the pump to the right without needing to lift it out. One thing I discovered when doing the above recently was that the pump doesn't necessarily end up in exactly the same position when refitted, leading to the coupling being out of true. I ended up having to use a small amount of leverage to keep the pump in line whilst tightening up.

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      Hello, I would like to ask if anyone out there knows the correct procedure for changing the coupling on the fuel pump of a jp3 ?
      Mine makes a clatter and I read it was common they wear here
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