Can not start jcb 3cx backhoe, help

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01293potter
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Can not start jcb 3cx backhoe, help

Post #1 by 01293potter » Sun Oct 11, 2020 7:20 am

Hi guys
I have had this backhoe for a year now and unfortunately it just just been a down hill experience:(

I’m unsure of the year of it but I’d say anywhere between 86 and 92 :?

So as the story goes I was having some issues with speed and power , I read on here about the filter so I had a look at that and it was brown so got new filter changed that over hen read that there was a filter in the injector so found that and it covered in crap cleaned them up dropped the old fuel as it looked bad then put 80 litres of new diesel in used the little hand pump to pump it round checked for air ect and now it just won’t start :thumbdown:
It just turns over but doesn’t ignite.
Any one ever had the same problem ?

Cheers in advance
Mat


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Re: Can not start jcb 3cx backhoe, help

Post #2 by essexpete » Sun Oct 11, 2020 10:44 am

What colour cab? Black or Grey originally. Have you got any smoke coming out of the exhaust when you are turning over? The most obvious thing would be to go through the bleeding procedure again. The final part would be loosening an injector pipe at the injector as you turn it over. Try that first.

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Re: Can not start jcb 3cx backhoe, help

Post #3 by Slooby » Sun Oct 11, 2020 11:20 am

Just been through this with mine; the manual (here) describes the bleeding process,but essentially:

Crack the fuel outlet union on the debris trap (chassis leg) and the gravity feed from the tank should force fuel out of it then tighten up the union
Move to the fuel filter (on the engine), crack the fuel outlet union then on the mechanical lift pump pump the manual overide lever until fuel starts coming out. Tighten up the union.
Now move to the mechanical injector pump and there are two bleed screws on the pump body (you'll need to refer to the manual for the positions) crack the lower one and manually pump the lift pump till fuel comes out, tighten the bleed screw, move to the upper bleed screw and repeat.
Now ideally you need an assistant for this, wear fuel proof gloves and get a rag; go to the injector furthest from the pump and crack the inlet union, get your assistant to briefly crank the engine, while you with rag in hand watch the union when fuel starts coming out of the union catch it with the rag, stop cranking and tighten the union, repeat for the next injector working back towards the pump and so on. If you are unlucky, like I was, you may have to repeat the injector bleeding a couple of times. Mine actually fired up by the time I'd got to the last injector on the third attempt. It's a matter of perservering with it till all the air is removed.

Fiddle with anything on the fuel system on these and you need to bleed them
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Re: Can not start jcb 3cx backhoe, help

Post #4 by 01293potter » Sun Oct 11, 2020 1:03 pm

Slooby wrote:Just been through this with mine; the manual (here) describes the bleeding process,but essentially:

Crack the fuel outlet union on the debris trap (chassis leg) and the gravity feed from the tank should force fuel out of it then tighten up the union
Move to the fuel filter (on the engine), crack the fuel outlet union then on the mechanical lift pump pump the manual overide lever until fuel starts coming out. Tighten up the union.
Now move to the mechanical injector pump and there are two bleed screws on the pump body (you'll need to refer to the manual for the positions) crack the lower one and manually pump the lift pump till fuel comes out, tighten the bleed screw, move to the upper bleed screw and repeat.
Now ideally you need an assistant for this, wear fuel proof gloves and get a rag; go to the injector furthest from the pump and crack the inlet union, get your assistant to briefly crank the engine, while you with rag in hand watch the union when fuel starts coming out of the union catch it with the rag, stop cranking and tighten the union, repeat for the next injector working back towards the pump and so on. If you are unlucky, like I was, you may have to repeat the injector bleeding a couple of times. Mine actually fired up by the time I'd got to the last injector on the third attempt. It's a matter of perservering with it till all the air is removed.

Fiddle with anything on the fuel system on these and you need to bleed them



Hi mate
Thank you! I will try this all out when I finish work tomorrow and let you know the results.

One more thing as I was tinkering around the machine I found that the thermostart had no current should it have a constant 12v to it ?
Thanks again
Mat


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Re: Can not start jcb 3cx backhoe, help

Post #5 by 01293potter » Sun Oct 11, 2020 1:07 pm

essexpete wrote:What colour cab? Black or Grey originally. Have you got any smoke coming out of the exhaust when you are turning over? The most obvious thing would be to go through the bleeding procedure again. The final part would be loosening an injector pipe at the injector as you turn it over. Try that first.

Hi mate
The cab is grey
I saw a little bit of smoke come out the exhaust today. I’ll go through the bleeding procedure again like you say
Thanks
Mat


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Re: Can not start jcb 3cx backhoe, help

Post #6 by agrimax » Sun Oct 11, 2020 6:26 pm

The thermostart should only have 12v to it when the key is held in the heat position.


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Re: Can not start jcb 3cx backhoe, help

Post #7 by topkit » Tue Oct 20, 2020 11:34 am

Its possible you could have a bit of crap in the fuel line between the tank and the injectors i had this on an old 3c mk2 several years ago. But if yo u say you have started to get smoke coming out of the exhaust i would say you still have a bit of air in the system, you could give it a squirt of easy start and see if that get you firing and then drawing the fuel through.


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