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Lewis Garner

Jaguar J60 carb diagram

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Hi all,

I'd appreciate it if anyone could come up with a carb diagram/drawing for the J60 carburettor. Ours still isn't running quite right so we've decided to have a look at it again, does anyone have instructions for where the mixture screws should be set? Any information is appreciated.

Regards, Lewis.

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Does it say Marcus on the flat mounting plate at the bottom of the carb? If not then it is an un-modified one and they don't run as well as the later ones.

 

In my experience some carbs just don't run as well as others no matter what you do, but we have a stillage full of old carbs so we just try another one. They do benefit from being ultrasonically cleaned.

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Hi Vince, well it says Marcus on the top of the carb body. As dad said, Terry Brooks' Scorpion was so easy to drive in comparison to ours. Plenty of power, you could easily start off in 3rd gear (a no no in ours), take your foot off the throttle at junctions, the clutch disengages and you just select whatever gear you like to start off again.

With ours it just isn't quite there, as dad said he'd feel a lot more confident taking ours on the road if it ran better, if you could tell us the location of the idle screw I'd appreciate that, as it needs turning up a little. If you feather your foot on the throttle it idles okay, take your foot completely off and it stops. That's the main problem at the moment, getting into forward and reverse, and having to select 1st gear whilst also keeping your foot feathered on the throttle. We've got an engine to collect from Marcus Glenn soon so if push comes to shove we'll just swap the carbs over.

Regards, Lewis

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The idler screws are on the base plate of the carb towards the front of the engine. Sounds more like you need to adjust the slow running screw which is on the rear of the carb near the drivers firewall. You should be able to tweak it with your fingers. Tickover should be about 600 RPM when the engine is warm. If I remember I'll take a photo of a carb when I get home and post it up. Packing for hoiliday tonight so can't promise!

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Lewis,

 

The J60 will struggle to run nicely untill it's warm, getting in a cvrt when it's cold and expecting to pull away like in a car won't happen. You need to warm the engine up first, there should be a wing nut on the throttle linkage so you can set the revs with the pedal and lock it off. A couple of minutes at around 1500rpm should do the trick. The idle should be around 600rpm as Vince said, the cluch kicks in at around 850rpm.

 

I do have a manual somewhere which has the tuning instructions, but it's the same as a Ferret. From memory... you need to do it with a warm engine, screw in both mixture screws and screw them out 1.5 turns and then screw them in untill engine speed increases. You need to make sure you adjust both mixture screws by exactly the same ammount.

 

I tuned up the Spartan as it was running a bit rich, it now idles at 600rpm and you can hear the generator louder than the engine. The engine in the Sabre is exactly as it came out of the crate, it was a factory re-con and ran perfectly straight out of the box.

 

I hope this helps,

 

Chris

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Hi Lewis, here are the pictures. They first one shows the 2 mixture screws which are the 2 screws at the bottom of the picture on the mounting plate. It says Marcus between the screws if it is a later, modified carburettor.

 

The second picture shows the idling screw. It is to the right of the rod and has a spring beneath the head. (The CVRT installation will not have the rod on it, I think this one is from a Fox). When on the engine the screw is towards the rear of the vehicle next to the drivers fire wall. Screwing it in will increase the idling RPM.

 

Like Chris has said, make sure the engine is warm before touching any of this. Also, how old are the spark plugs? New spark plugs cure many bad running problems on CVRT engines. Some carb cleaner would be a good idea in the fuel tank if your CVRT has been standing for a long time, and fresh petrol always helps as modern fuel goes off quickly.

 

Hope this helps.

Image013.jpg

Image012.jpg

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Hi chaps, thanks so much. As you say Chris of course wait till the engine is warm before turning any screws. Even after warming it up for a few minutes and taking it up and down the track a few times, it still won't idle. The pickup from idle is rocky too even when warm, so obviously something is amiss.

Thanks to Vince too, that is a BIG help. I had a vague idea of where everything was but obviously you don't want to go adjusting any screws when you're not 100% sure what they are. Hopefully a little adjustment, and then we can take her out on the road for the first time.

Thanks again,

Lewis

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To report back after some tinkering with the carb. She's now running a lot better after 20 minutes of adjusting the mixture screws.

One of them was screwed almost right in, the other was a little too far out. That done, obviously it ran much more smoothly than before but still the idle was too low. Found the idle screw round the back (a fiddly one on the Spartan) and managed to turn the idle up. Runs sweet as a nut now.

Thanks and regards,

Lewis

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Lewis,

 

I'm glad to hear it's running better now. Will you be bringing it to Beltring? If you do, don't leave it parked anywhere near Vince, he's very keen on taking Spartans apart at that particular show!

 

Chris

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Hi Chris,

I'd say probably not, dad likes a good night's sleep! :D The costs of transporting it and possibly the Ferret there wouldn't really be feasible but of course we will go as visitors, hopefully we'll see you all there. At least that means our vehicle will stay in one piece when it's out of Vince's reach :D

Regards, Lewis

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I'd dearly love to not have to take mine apart! Having just re-engined it, fixed the final drive and sorted a gearbox leak I went for a test drive on Monday. Ran really well (better than ever in fact) but when I got back I discovered it still has a gearbox leak. The gearbox was a re-con too after the main shaft broke. I'll have to take it out again, hopefully before Beltring as I don't want to lose the steering again having fitted new steering pads. One day it will be right!

 

At least all the current problems became apparent from using it- in previous years it's been a struggle just to get it running. Being one of the first batches of CVRT's released from the Army it was rebuilt out of bits the army threw away because they didn't work properly. The parts situation was not great when we first got it, now you can get most bits quite easily. It's had about 3 engines, 3 gearboxes, 2 control boxes a new set of idlers, sprockets and tracks, a new glacis plate, the list goes on.

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Dear All, if I may high jack this old thread. In getting my j60 back on the road following a broken exhaust valve ( and piston), I remember having a problem trying to start it. It only coughed when I poured a little of petrol down the throats, so I suspect a blocked jet. Being a solex (non Marcus) I'm assuming that with the float chambers full, if you open the throttle you should also get a jet of petrol squirted into the throat, like a landrovers carb does. Am I right? If the main jet is blocked could someone point out which one it is? I have no manuals. Grateful for some help, I'm still after 2 Pistons (std size) as none of the businesses seem willing to sell anything less than a full set.

regard

Andrew

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Before getting into the fine aspects of jet cleaning, are we sure that fuel is getting up to the carbs, and that float chamber has fuel in it?

 

trevor

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The carburettor on the J60 is fundamentally the same as that on a Daimler Ferret, albeit a slightly larger version with a different design for the altitude compensation.

 

If you look on the Daimler Ferret website there should be enough info there to determine how the carburetor works and how to strip it.

 

Problems arise from dirt in the jets and body as well as two internal gauze filters, Air Leaks through worn shafts, faulty seals and gaskets and stiff or punctured diaphragms caused be old age as well as incorrect idling and mixture adjustment.

 

Its also possible that the accelerator pump linkage is seized.

 

Diana

 

 

 

 

 

Dear All, if I may high jack this old thread. In getting my j60 back on the road following a broken exhaust valve ( and piston), I remember having a problem trying to start it. It only coughed when I poured a little of petrol down the throats, so I suspect a blocked jet. Being a solex (non Marcus) I'm assuming that with the float chambers full, if you open the throttle you should also get a jet of petrol squirted into the throat, like a landrovers carb does. Am I right? If the main jet is blocked could someone point out which one it is? I have no manuals. Grateful for some help, I'm still after 2 Pistons (std size) as none of the businesses seem willing to sell anything less than a full set.

regard

Andrew

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Hi chaps, thanks. Fuel is definitely filling the float chamber, but not sure where it is then going to. The carb looks in very good nick, the engine had done very few miles since its rebuild. I think I might need to have a look at the pumps on each side, and finally, looking down the choke Venturi, I assume the choke is off with the small butterfly flap open? This suggests to me that the choke rod has to be pushed on rather than pulled on?

Regards

Andrew

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Andrew.. Diana is not a chap!

 

Diana

 

 

Hi chaps, thanks. Fuel is definitely filling the float chamber, but not sure where it is then going to. The carb looks in very good nick, the engine had done very few miles since its rebuild. I think I might need to have a look at the pumps on each side, and finally, looking down the choke Venturi, I assume the choke is off with the small butterfly flap open? This suggests to me that the choke rod has to be pushed on rather than pulled on?

Regards

Andrew

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Sorry, I did know that, it's my collective term for than one person.. I do the same at work with 5 blokes and 2 women. Lazy...

Your input input much appreciated.

Andrew

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Posted (edited)

Resurrecting an old thread again, does anybody have details on setting the float height on a CVRT carb? I'm contemplating building up a good one using a rebuild kit and it would be good to be able to check that the float heights are correct.  Doing this on my MUTT made a big difference to how it runs! And yes I still seem to be taking Spartans to bits as suggested further up the thread...getting there slowly!

Edited by Grasshopper

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