Oil & Fuel Fuel System Problem John Deere 5720

[scottkerslake]

My JD 5720 has only done 2000 hours and it is suffering from a fuel issue that Im yet to get to the bottom of. I have replaced all the fuel lines on the suction side of the injector pump as well as both filters but I'm getting air in the system. After about 10 mins at 2100 RPM it starts " hunting " and blowing smoke at the same time the rpm drops down to 1100RPM or there abouts at full throttle . I stop the tractor bleed the system and air is present where could this be coming from?? Im thinking that the water separator filter housing my be defective or the small inline prime pump. Has anyone out there in tractor world had this problem? Have tried asking local JD service center but all there interested in is coming out to take a look themselves and charging a small fortune for the privilege to do so.
HELP!!!!

 

[Tx Jim]

I wonder if the suction tube(parts key #5) could have a small crack in it??

 

[Kyle_in_Tex]

Change your fuel lines first. They are notorious for cracking.

 

[kuboman]

My JD 5720 has only done 2000 hours and it is suffering from a fuel issue that Im yet to get to the bottom of. I have replaced all the fuel lines on the suction side of the injector pump as well as both filters but I'm getting air in the system. After about 10 mins at 2100 RPM it starts " hunting " and blowing smoke at the same time the rpm drops down to 1100RPM or there abouts at full throttle . I stop the tractor bleed the system and air is present where could this be coming from?? Im thinking that the water separator filter housing my be defective or the small inline prime pump. Has anyone out there in tractor world had this problem? Have tried asking local JD service center but all there interested in is coming out to take a look themselves and charging a small fortune for the privilege to do so.
HELP!!!!

Had a similar problem with an old international tractor. Problem I had was there was a tube in the fuel tank that had been dropped in. It would roll around in the tank until it blocked the fuel suction line. In doing that it caused reverse flow through the return which was above the fuel level in the tank. This would suck the fuel out of the filter and then the engine would stumble and quite. I would bleed the system and away it would go sometimes for hours sometimes for minutes. Very confusing until I discovered the debris in the tank.

 

[Tx Jim]

Kyle_in_Tex
You must have overlooked this statement.

I'll quote scottkerslake [I have replaced all the fuel lines on the suction side of the injector pump as well as both filters]

 

[scottkerslake]

Done that as well as drained fuel tank checked fuel pickup and added an anti algae supplement to a fresh batch of fuel.
Im trying to cover all basses at the moment.

 

[scottkerslake]

Has any one replaced the water seperator filter with a non genuine like raycor or the like?

 

[jd110]

I don't have any experience with aftermarket filters. I was looking at the diagram for fuel hoses on your tractor. It is somewhat different than our North American tractors but similar. Are your fuel lines like this? I see several connections that could be source of leak. Besides the obvious hose conenctions, there are three quick connects on primary filter and suction side of pump that could leak. (items 12 & 15)and check valve (item 17). Another item to look at is the orifice (item 41). It can get clogged and cause excessive pressure to injection pump and can make automatic purging of air not work as well. If the orifice is missing, it can cause insufficient pressure to injection pump due to too much fuel dumping back to the tank. I have seen alot of these orifices missing when someone replaces the hose without reinstalling the orifice.

 

[scottkerslake]

My machine doesn't have that spill back line where item 41 is located. When I replaced all the fuel lines I did away with those quick release type hose clips (that come from factory) with worm type hose clips to eliminate problems at connections. The only item I haven't looked at is that check valve (item 17). I was reading on a forum the other day a guy said every time that John Deer service guy comes out to do a service he replaces the water filter & housing every time so that's why I'm wandering if the factory one is no good.
Because of the distances here in Australia the service agents charge like wounded bulls just to get to ya machine that's why I'm doing it myself.

 

[scottkerslake]

I will check that thanks!