1971 JCB 3c MKII Servicing and Renovation

[MrF]

I would also check the fuel filters, its pretty common for the bottom of the tank to be full of decades of crap. On mine the seller changed the filters just to get the machine on the transport, when it arrived it seemed to run ok at first then started to plug the mesh filters up quickly then I discovered the new fuel filter canisters fitted had no insides and had to venture down the road of diesel pump repairs because all the crap got dragged into the pump and that is a very bad thing indeed.
If you have to change the replaceable filters, there is a non disposable mesh filter in the top of the lift pump that you can clean out also. the top cover of the lift pump is secured by a single screw in the middle if its the same as my two, and there is a gasket that might fall to bits when you do this to be forewarned. I found a large fuel safe rubber washer at the tractor parts shop to reseal mine and the trick seems to be to not to overtighten the screw when you put it back together as it can distort the pressed cover easy. Also added a extra inline water trap before my fuel pump and new filters of course.

The fitting that screws onto the bottom of the fuel tank that the fuel pipe goes onto has a mesh filter in it also if its still there, Ive seen some machines that have a extension soldered in to get past the layer of crap at the bottom of the tank as a stop gap. I suppose its a idea but when the machine tilts on a grade it still lets the fuel swill the dirt into the system.
A lot of these machines when neglected over the years suffer from issues with dirty fuel, as the only really effective way to clean the tank out long term seems to be to cut a access hole in the top of the tank as its part of the machine's principle main frame. I've swilled mine out because of dirty fuel issues and I'll do this when I get some of the more pressing issues fixed. The 3c2 I just broke had a patch on the top of the tank where someone had done this in the past.

[Matchless?58]

Hi I had the same problems with the machine being starved of fuel . I had already fitted an inline filter into the fuel line directly from the tank because the machine hadn't been used for some time prior to me buying it and I suspected that the tank would be full of crap . This filter saved all the rubbish from being pushed through the fuel pump . It kept getting bunged up about every five minutes at one point . This was a nuisance and I was changing the filter for a clean one all the time .
My solution ?
I have no cab on my machine atm as its in a bit of a state and ive yet to start renovating it so I waited for a bit of hot weather then drained all the fuel from the tank . Then removed the fuel gauge from the top of the tank . I got the lance of my pressure washer through the fuel gauge hole and basically blasted it from all angles for about 2 hours its amazing how much rubbish and bits of rust etc floated out the top of the tank . I did the same the next day and added washing up liquid and then another thorough rinsing . I then let it dry completely . I filled up with fresh fuel and I have had no more trouble since . My additional filter has a tiny bit of muck in it but doesn't need changing yet .
Another problem with these tanks can be condensation which forms in the tank particularly in the winter months and then water gets in the fuel so it pays to top the tank up as full as possible in the winter especially if the machine is standing idle .
Cheers Chris

[acstechnology]

Thanks again guys, sounds like good advice, I'll have a look at all that this weekend, hopefully the weather won't hinder progress

Kev

[acstechnology]

Can anyone here upload a photo of there 3ç MK2 fuel cap with measurements so I can find a replacement please

Thanks
Kev

[essexpete]

Can anyone here upload a photo of there 3ç MK2 fuel cap with measurements so I can find a replacement please

Thanks
Kev

Might be possible to source from breakers? Is the filler in front of the screen or under the cab step?

[acstechnology]

It's under the entrance

[MrF]

Let me find the one I have kicking about and get a shot, it looks like a radiator cap gone wrong.

[acstechnology]

Let me find the one I have kicking about and get a shot, it looks like a radiator cap gone wrong.

That would be brilliant thanks mrF

[MrF]

Here, though I'm not certain its the proper cap anyway as it looks like a actual radiator cap complete with warning about releasing slowly. The machine its off was the same model as yours with the diesel filler under the door (behind a external door which I've already cut the front hinge area off to repair my hydraulic door hinge with...) You can have the cap if you want it, or I can take a extra shot with a ruler showing the sizes. I sent you a pm.

[CHRISEEBOY]

I'm in the same boat MrF, currently using a rubber glove as a fuel cap!

If you could take a shot with a ruler like you said we might be able to source a replacement.