JD 310 BACKHOE HARD STARTING AFTER SITTING 2-3 DAYS!

ken higgins · Jul 29, 2017

My 1994 JD 310 backhoe will not start if it sits for 2-3 days. I have to hand prime fuel pump and use starting fluid. It has to run on starting fluid for 10-30 seconds then it gets fuel and runs like a top all day. If I start it every day this problem goes away. Any ideas where to look?

Tx Jim · Jul 29, 2017

Welcome to TBN
Sounds as if fuel is leaking back to tank. It's possible fuel line has a crack in it or check valves in lift(transfer?) pump have failed. One option would be to install a check valve between fuel tank & lift pump.

thepumpguysc · Jul 30, 2017

I believe it has a lift/supply pump on the engine.. it sux fuel from the tank, pushes thru the filters & then to the inj. pump..
They are very inexpensive to replace..

Dave M7040 · Aug 22, 2017

On some older tractors, I cannot say if your is one, the fuel return line from the injectors is dumped into the main fuel tank.

In the beginning with a new tractor, this return line extended down to almost the bottom of the tank. Over time this line inside the tank would break off from vibration. There would be no external leak for you to see but what would happen is that as the engine and fuel cooled down, this return line, which should have been submersed in the fuel but is not, being at the top of the tank inhales air as the system cools down rather than siphoning fuel from the tank to keep the system free of air.

Using ether is not getting you to a good place with your engine.

Do you have glow plugs? Do you know if they work and if so how?

The lift pump is likely a mechanical pump. Adding a low pressure electric pump in series with the mechanical lift pump gives you the opportunity to easily bleed the injector pump before trying to start the engine. Likely around a $50 investment.

Dave M7040

Tx Jim · Aug 22, 2017

Dave M7040
JD 310 didn't have glow plugs. Fuel return line to tank only enters tank neck a short distance nowhere close to bottom of tank. IMHO return line getting air in it will not affect if engine runs or not as I've had several different brand diesels engines running with fuel return lines loose. I agree with you that use of ether on JD 300 series engines can crack top piston rings & ring lands which lowers compression making these engines even harder to start. Factory lift pump is mechanical type.