Newbie 3C late 70s model losing power

[mcdoo]

Hi
I've acquired a JCB 3c for a renovation job at home. It's end of life I suppose but the brilliant engine starts on the key every time without fail and it will dig all day (until lately) The cabs rotten but its a great machine for odd jobs. There is an intermittent hydraulic leak at the steering but doesn't effect performance, however lately it has been losing power especially during back actor work when the engine fades away and dies. Just today it would hardly drive up a small hill without revs dying off and stopping. I know nothing about 3Cs but would appreciate it if somebody could float a few possible solutions.

On the back actor issue, I've A TEENAGE BOY who begged to do some digging in a field. What can you do! I set the 3c up and let him learn while watching nearby, however, when he got bored the left hand lever that guides the arm left and right was loose and floppy although it still worked. I noticed though that when moving the lever left or right it had a chugging effect on the engine and one of the small rams (if that's the right word ) under the lever doesn't spring back into place. Thanks in advance

[agrimax]

Welcome along. I would suggest changing the fuel filters first. Sounds very much like dirt is causing your problem.Quite likely too that the plastic gauze below the inlet pipe on the end of the injector pump will need cleaning.Need to be careful dismantling that bit as the valve bits inside often come dislodged and the engine won't go again til it's reassembled correctly.

Would suggest that a lever not returning by itself could be a rusty or distorted spool,weak or broken spring(below the cap under the spool on the bottom of the valve block,relative to the spool in question) or a piece of rubber seal(o ring) stuck in a groove on the spool rod.

[mcdoo]

Thanks for the reply. The engine idles fine. Would this still point to the filter? It seems to stop under load.

[agrimax]

It could do.Filter not letting enough fuel through for load but enough for idling.Start with the easiest things first.There are other possibilities,such as the pump being full of gunge etc or the aforementioned valve sticking,that the gauze in the end of the inj pump sits around.Is the supply from the fuel tank clear? Go there first.Then the lift pump.
Lift pump IIRC,should have a gauze under the lid.Could just need cleaning.Lift pump could be weak or the lever that the camshaft pushes against to make the lift pump work,may be worn. Take off the outlet pipe from the lift pump and crank the engine over.See if there is a good supply of fuel from it.If so,move on to the filters.Change the filter/s anyway.They're cheap.When you're sure the thats all good, you're down to the injector pump.

[Jeremy Rowland]

A cheap easy tip; take out the air filter and check that is not clogged up, you'd be surprised the difference it can make, then go for the fuel filters. Jim welcome to the forum.

Jeremy

[agrimax]

Sure I forgot about the air filter too!!

[TullyveeryClassicJCB]

I had a 3C that had the same problem with a floppy lever except mine was the lever for the loader. On a cold engine sometimes it wouldn't start because the bloody lever would have fell into the raise position. When you were driving along and hit a bump all of a sudden it would raise or lower depending on which way the lever fell.

[mcdoo]

Thanks guys. I'll try your suggestions and let you know.