Hi, I have an old JCB 3C which I was using until the engine stopped ! I assumed as the fuel gauge does'nt work that I had ran out of fuel :Banghead so I primed the pipes etc from the fuel pump and can got it started ok, Problem is when its running I can see air bubbles travelling through the fuel pipe from the pump, the engine will idle ok but when I give some acceleration the engine cuts out within 60 seconds clearly due to the air in the fuel, I cant work out if I actually run out of fuel now or the air bubbles occured causing this problem, Can anyone tell me how air is getting into the pipe as I cant understand how air can get in through the fuel tank yet I cant see any leaks in the pipe ! Any help is appreciated as I know my way around an engine but am no mechanic Thanks
Hey Alfy101, I would try pressurizing the tank a bit with an air compressor then check all the fuel lines for leaks especially on the suction side of the pump, if there is any they should show up under pressure.
That square rubber o-ring that goes in the groove of your water trap base is a good location for them to suck air.
I had the same problem on mine. The fuel line had a small crack and was sucking air. Mine would run OK after you got it started but getting it started was a problem. If it sat for more than a day it had to have ether even when it 60+ degrees out. Now it pops right off. Rick
same as above post, i had one that would go good days,weeks then play up and would not prime, it had cracked fuel line behind the engine, it did not leak but would suck air.
If you have one that doesn't leak but sucks air shaving cream can be a good way to find the spot. Taught to me by a old fuel injection man.
Thanks for all your help lads, found a small crack in the pump housing that was not leaking fuel but sucking in air, Should hopefully be ok after I replace the pump