runs fine then dies 543-b--kubota d 950

[buddy]

I have what I believe to be a fuel problem ? runs good for @ 20-30 minutes then just dies slowely like fuel starvation ? wait 10 minutes than re start and fine for @ 5 min. and dies. have replaced the entire fuel line from inside tank down past primer bulb.The filter is also new. That being said I would like to know if an electric fuel pump installed AFTER the filter and BETWEEN the engine might add enough boost to possably cure the problem. have checked the search and can only find limited information on this topic can anyone chime in with possable solutions or will this trick work. Oh and shut off the valve is open. Thanks Mark

 

[OldMachinist]

First thing that comes to mind is the vent in the fuel cap is clogged. Try running it with cap loose and see what happens.
Also what does the primer bulb look and feel like when it first dies?(sucked flat, firm or squishy)

 

[buddy]

First thing that comes to mind is the vent in the fuel cap is clogged. Try running it with cap loose and see what happens.
Also what does the primer bulb look and feel like when it first dies?(sucked flat, firm or squishy)

Actually drilled small hole through fuel cap as I also thought that might be the cause . The primer bulb looked fine l did squeze it but it seemed full hard to squeeze. I loosened the in,jector bleeder and than it would squeeze but would stay squished. There is another line on the tank that goes to the rear injector like a possable return line . Could it be plugged and stopping the fuel from circulating or am I on the wrong track there ??? What is the part on the motor called that the fuel line connects to? Is this a pump ? Thanks

 

[Clyde]

Actually drilled small hole through fuel cap as I also thought that might be the cause . The primer bulb looked fine l did squeze it but it seemed full hard to squeeze. I loosened the in,jector bleeder and than it would squeeze but would stay squished. There is another line on the tank that goes to the rear injector like a possable return line . Could it be plugged and stopping the fuel from circulating or am I on the wrong track there ??? What is the part on the motor called that the fuel line connects to? Is this a pump ? Thanks

Just went thru a similar problem on my 773, turns out it was the pickup tube in the tank, it was split, and sucking a little air, which was then air locking the injector pump. New pickup and screen fixed it right up for me.

 

[[email protected]]

Just went thru a similar problem on my 773, turns out it was the pickup tube in the tank, it was split, and sucking a little air, which was then air locking the injector pump. New pickup and screen fixed it right up for me.

when you open the bleeder, and squeeze the primer bulb, it should get firm. if it stays sucked in something is creating a vacuum

 

[lfutrell]

when you open the bleeder, and squeeze the primer bulb, it should get firm. if it stays sucked in something is creating a vacuum

I don't know if it is the same as a 743 or not, But on the 743 there is a channel behind the fuel tank that the fuel lines run thru, sometimes these lines get out of the channel and get smashed between the tank and the back

 

[Cstraley]

I don't know if it is the same as a 743 or not, But on the 743 there is a channel behind the fuel tank that the fuel lines run thru, sometimes these lines get out of the channel and get smashed between the tank and the back

Help, I too have the exact same problem with my 543B, which is why I joined this fine forum full of good information. Thank you in advance. I'm having the same "runs fine for 5 minutes then dies". It does seem like a fuel delivery issue. It dies slowly. I too checked the cap and the primer bulb, and it doesn't appear to be a vacuum. I took the fuel cap off tonight while it was dieing and I rocked the machine around and it sputtered out quickly. If I let it sit for a while I can run it again for five minutes. There were small black plastic rubber particles in the fuel filter. We changed it and primed it and the problems occurred again, just as before. The filter didn't help. I think it is the fuel pick ups. 1. What is involved with lifting the cab and removing the tank and old lines? 2. Where to begin? Thanks! Chris

 

[antfarmer2]

Help, I too have the exact same problem with my 543B, which is why I joined this fine forum full of good information. Thank you in advance. I'm having the same "runs fine for 5 minutes then dies". It does seem like a fuel delivery issue. It dies slowly. I too checked the cap and the primer bulb, and it doesn't appear to be a vacuum. I took the fuel cap off tonight while it was dieing and I rocked the machine around and it sputtered out quickly. If I let it sit for a while I can run it again for five minutes. There were small black plastic rubber particles in the fuel filter. We changed it and primed it and the problems occurred again, just as before. The filter didn't help. I think it is the fuel pick ups. 1. What is involved with lifting the cab and removing the tank and old lines? 2. Where to begin? Thanks! Chris

Air filter?

 

[Cstraley]

Air filter?

I bought the 543 B used at a local Ag store. They fully serviced it with new filters and oil, and even put a nice maintenance log sticker on the inner rear gate. I have virtually no hours on it since purchase one year ago. We bought it with no warranty one year ago for snow removal and didn't get any snow last year. So all I've done is move it around and move a few piles of stones. Runs ok for the first 5 minutes. Checking the forums here it really sounds like a rotted, split, or clogged fuel hose pick up. I will check the air filter though. I have no idea how to access the tank and replace lines. I know the cab lifts up but havent done it. Any advice? Thanks...Chris

 

[antfarmer2]

I bought the 543 B used at a local Ag store. They fully serviced it with new filters and oil, and even put a nice maintenance log sticker on the inner rear gate. I have virtually no hours on it since purchase one year ago. We bought it with no warranty one year ago for snow removal and didn't get any snow last year. So all I've done is move it around and move a few piles of stones. Runs ok for the first 5 minutes. Checking the forums here it really sounds like a rotted, split, or clogged fuel hose pick up. I will check the air filter though. I have no idea how to access the tank and replace lines. I know the cab lifts up but havent done it. Any advice? Thanks...Chris

I have a 743 so just a thinking does yours have a bulb to prime the fuel if so start it and see if it sucks in if so pinched line of crap in line or tank

 

[antfarmer2]

I have a 743 so just a thinking does yours have a bulb to prime the fuel if so start it and see if it sucks in if so pinched line of crap in line or tank

Or sitting so long bad or water in the fuel hook up a fresh aux tank and tie it in

 

[Cstraley]

Or sitting so long bad or water in the fuel hook up a fresh aux tank and tie it in

I'll have to see if its sucking the primer bulb in. I did have a friend replace the fuel filter even though it was only a few hours old from dealer, 6 months later. Non use. It wouldn't be impossible to rig up a temporary auxiliary fuel tank. In fact I have one for working on motorcycles (by motion pro). The fuel filter had chunks of black rubber in it so I'm fairly certain this would be the problem, the pick up tube. The tank on the 543 is high and right behind upper body portion of seat. Where the lines go in and out I can examine once I figure how to lift the cab and gain better access to the tank. With an auxiliary tank installed for temporary fuel do you have to worry about the return line that would go from the end of the injectors back to the tank? I think I read that about a return line somewhere.

 

[antfarmer2]

Or sitting so long bad or water in the fuel hook up a fresh aux tank and tie it in

It looks close to mine on mine you have to take off the nuts around the seat on the cage 4 I think and the cage just pivots up on the right side I have two connectors that have to come apart and from there you will see just be careful picking the cab up slippery where I had to stand will be putting new gripper tape lol

 

[antfarmer2]

It looks close to mine on mine you have to take off the nuts around the seat on the cage 4 I think and the cage just pivots up on the right side I have two connectors that have to come apart and from there you will see just be careful picking the cab up slippery where I had to stand will be putting new gripper tape lol

You should be ok as long as your tank is not to full and you over fill it with the return also look under the tank and see if you have a shut off like mine tucked up there if so you can use it for trouble shooting and to hook your temp tank to

 

[Cstraley]

You should be ok as long as your tank is not to full and you over fill it with the return also look under the tank and see if you have a shut off like mine tucked up there if so you can use it for trouble shooting and to hook your temp tank to

Ok thanks for the advice. I know my 753 has dual lift arms compared to single on the 543 but I guess it lifts up the same. I never lifted either. I will siphon the fuel out of the main tank first as its full now. I will look for the shut off in case it has one. I think its going to rain here tomorrow and it's been raining most of today so a good day to take a look at it.

 

[Cstraley]

Ok thanks for the advice. I know my 753 has dual lift arms compared to single on the 543 but I guess it lifts up the same. I never lifted either. I will siphon the fuel out of the main tank first as its full now. I will look for the shut off in case it has one. I think its going to rain here tomorrow and it's been raining most of today so a good day to take a look at it.

We also put a whole bunch of diesel fuel treatment in it to see if it was a water or poor fuel situation. I think not as it runs great until it runs out of fuel. Someone said gasoline will cause behavior like that too. Not sure how to test for that. I guess just drain it all and get all new. One odd thing I forgot to mention is the throttle on the 543 revs the rpm if you pull it back or push it forward with a lull in the middle position to idle down. I don't think its related but just remembered that quirk.

 

[buddy]

I don't know if it is the same as a 743 or not, But on the 743 there is a channel behind the fuel tank that the fuel lines run thru, sometimes these lines get out of the channel and get smashed between the tank and the back

Ifutrell was exactly right my fuel line was crushed behind the tank in the exact same area. replaced the line made sure in was placed in the tank groove and now she runs fine... thanks for all the help everbody. 543/743 SEEMS THIS IS A COMMEN PROBLEM...the line on mine was about 3" to short to go conpleatly in the grove the bottom corner was crushed . Buddy

 

[lfutrell]

Ifutrell was exactly right my fuel line was crushed behind the tank in the exact same area. replaced the line made sure in was placed in the tank groove and now she runs fine... thanks for all the help everbody. 543/743 SEEMS THIS IS A COMMEN PROBLEM...the line on mine was about 3" to short to go conpleatly in the grove the bottom corner was crushed . Buddy

Glad you found it.

 

[Cstraley]

Glad you found it.

Ok, I ran the 543 until it started sputtering out and sure enough the fuel primer bulb collapsed during the last few moments of it cutting out. It then stayed collapsed for a while and I was able to start it later but just for a few seconds. Today it ran well for a few minutes and I put it in my shop. I'm hoping there is room to lift the cab in there. I think the ceiling is 9 feet. I'm going to try to trace the line back and replace it inside the tank as it seems like that is certainly the problem. Five minutes of run time till debris gets sucked back up on the screen or a split hose. Either way it's got to come out.