M5040 Fuel Problems

[bmcdonald5674]

I had some rubber get into my fuel tank by accident and degrade. It got all the way to the fuel/water separator and clogging it up. After cleaning the filter in the bowl twice the engine stopped completely. I have taken the tank off and cleaned, blown through all lines. Replaced the filter in the separator bowl and the main fuel filter. I still did not have any luck so thinking the fuel pump was trashed I replaced it. I know I am getting fuel to the new mechanical fuel pump but still nothing comes out of the pump. I disconnected the fuel line after the separator bowl and did not get anything out of the line while turning the key and having the starter turn the motor over. I have trimmed the supply fuel line to the fuel pump and installed a new clamp. I had filled the separator bowl with diesel as well as the new fuel filled before installing them. I disconnected the fuel line after the fuel filter and tried using the prime pump on top of the filter cannister but got nothing out of it. I used a vacuum pump to ensure I was getting fuel from the tank to the pump. The check valve in that line is definitely working. You cannot blow back into the tank. Please help me. My tractor is broken down in the woods in a very rural spot and would be difficult to load even on a drop back wrecker. Please anyone, I need help! Thank you!

 

[Captain13]

Could you have air in the line between the injector pump and the injectors? Crack the lines open at the injectors and bleed them then give it a try.

 

[bmcdonald5674]

Could you have air in the line between the injector pump and the injectors? Crack the lines open at the injectors and bleed them then give it a try.

I did that but I can't get fuel past the fuel pump with an open discharge side, the water separator with an open discharge side, or past the fuel filter discharge side. I am not understanding how I can't even get it from the tank past the pump. It has fuel to the pump but nothing comes out of the new mechanical pump when the engine is turned over. I can put vacuum on the supply side fuel line to the pump and I get fuel from the tank. I trimmed the hose and used a new clamp and hooked it back up to the pump. Still nothing comes out of the open discharge port of the pump. I also tried without the fuel cap thinking I might have a vapor lock on the tank. I also put vacuum on the line on the discharge side of the water separator and could not pull fuel out through it. Could the new pump be bad? Wouldn't be the first time.

 

[Captain13]

I’m not sure which fuel stop solenoid you have, (there are two types). I just replaced one on my zero turn. Mine actually moved a lever on the pump to allow fuel to go through. Could be that you can’t draw fuel through the pump unless the solenoid is energized to allow fuel to flow. I’m not familiar with which one your engine has. My early failure mode was having to turn the key on, throttle up until I heard the solenoid click, and then the engine would start. Problem was, I couldn’t shut the engine off without manually operating the fuel shit off lever on the pump. Here’s a video for you to look at that may help.

 

[bmcdonald5674]

I’m not sure which fuel stop solenoid you have, (there are two types). I just replaced one on my zero turn. Mine actually moved a lever on the pump to allow fuel to go through. Could be that you can’t draw fuel through the pump unless the solenoid is energized to allow fuel to flow. I’m not familiar with which one your engine has. My early failure mode was having to turn the key on, throttle up until I heard the solenoid click, and then the engine would start. Problem was, I couldn’t shut the engine off without manually operating the fuel shit off lever on the pump. Here’s a video for you to look at that may help.

Thank you so much. I also stopped by the dealer and talked with the service manager today. He told me this vintage Kubota is terrible about getting the air bled out. I actually ordered an electric fuel pump that is compatible with diesel from Jeg's this morning. I am going to bypass the mechanical pump and use this electric one to at least make sure I am getting the system full and the air out.

Thank you so much for the responses. I will take serious any and all to follow!

 

[North Idaho Wolfman]

Really simple fix to get it out of the woods:

Take a very clean container that you can attach a fuel hose to and that you can vent
fill it with very clean fuel, support it above the hood line and feed the fuel hose directly to the injection pump.
Don't bother with an electric pump, you will end up doing more harm than good.

Once in a suitable clean place to work on it, start from the tank and work all the way through the system.
Fuel separators, pumps, and filters do not like bulky crud in the input pipes and fittings.
Some separators and filter housings will have a screen on the input of the housing.

 

[whitetiger]

Sounds like you have a piece of the rubber plugging the inlet side of the water separator. Remove the separator, remove the bowl from it and blow backwards through the inlet side.

 

[bmcdonald5674]

Sounds like you have a piece of the rubber plugging the inlet side of the water separator. Remove the separator, remove the bowl from it and blow backwards through the inlet side.

Just an update. I appreciate everyone's input. It is very helpful. I went back up and once again tried to see if the new mechanical fuel pump would pump through an empty line into a bucket. It would not. I hooked up the electrical fuel pump I bought from Jeg's. I wired it with a momentary push button since I am working on this by myself. I purged through the separator (new filter) into a bucket. I repeated by connecting to the new spin on filter cannister. I then removed the fuel line at the banjo bolt going into the injection pump. All good. I reconnected and purged through the two outside injector hard lines. Once I did this I hit the starter and it cranked and ran great, even as I increased RPMs. So I thought well all the air is out let me reconnect the new mechanical pump being careful not introduce any air, It would not crank. So to me the new pump is defective or the check valve is not sealing totally and fuel is leaking back into the tank and the mechanical pump does not create enough lift to get it going from a not running condition. So I hooked the electric pump back up, held down the button to power it and was able to load it onto my trailer and get it home. Here is the crazy thing. Once the motor is running there is enough suction to the tank created that I could let go of the momentary push button and the tractor will run fine with essentially no fuel pump. To start it you have to push the button but I actually did some bush hogging around our barn and where I had my trailer parked before loading it without voltage going to the electric fuel pump. Was running the engine at 1600 rpm with the load of the bush hog and the motor never stopped running (without any fuel pump functioning), Is everyone in agreement about where I am at this point, check valve or defective mechanical pump? I would appreciate any further comments. Thanks for everyone's help! At least now it is home and I can get it to the shop.