Bobcat 763 fuel issues

[tomcat7810]

all I have an issue with my bobcat 763. Has the kubota v2203-e engine. The symptoms are that I was running it and it started to run and idle weird, then it shut off. I changed the fuel filter and got it primed up again and running, however the throttle is really unresponsive (doesn't change the throttle or is delayed if it does) it also doesn't shut of right away when you turn the key off. It actually takes a minute. Throttle linkage is fine and fuel shutoff solenoid is fine. They both are moving freely and staying in place. Any ideas? Not sure how to troubleshoot?

 

[willie59]

Is the tank completely full of fuel?

 

[tomcat7810]

Half to 3/4

 

[willie59]

Might try filling it all the way, a common problem with Bobcat machine is the flexible pickup tube breaks off inside the tank. Completely full it will run fine, once it draws down a bit it will start running funky and die

 

[thepumpguysc]

Fill the tank & try that first.
Next, Check the lift pump for flow.. loosen the inlet banjo bolt and spin the engine, it should squirt a lot of fuel..
Then, it sounds like the control rack is gummed up, which requires the inj. pump to be removed.
Did it happen all of a sudden?? has it been sitting unused for awhile?

 

[tomcat7810]

Tank is full. Still doing it. As I crank it over lift pump squirts fuel. Basically just oozes out, doesn't spray at pressure or anything but is pumping. What's the control rack? I see the feed from the tank goes to the fuel filter, then from there goes to the lift pump, then from the lift pump it looks like that goes into the injection pump, then from there there is 4 hard lines, each going to an injector.

 

[willie59]

Ok, sounds like your problem isn't a broken pickup tube inside the tank, and a faulty injection pump rack could be the problem. But before you tear into the injection pump assembly, one other common problem with Bobcat machines is the strainer on the end of the pickup tube is clogged. When this happens the rubber primer bulb in the fuel line will suck itself flat as a pancake when the engine is running. However, a hole in a fuel supply line from the tank will cause the engine to act this way as well. Before I go into the injection pump I would disconnect the rubber primer bulb from the line coming from the tank and connect a piece of fuel hose to the inlet of the primer bulb. Drop that hose in a clean can of fuel. Start the engine, even while pumping the primer bulb as the problem could also be the lift pump is failing. My objective is to make sure I'm getting fuel to the injection pump. If it still runs crappy after doing this, then I'm strongly suspecting a problem with injection pump. BTW, make sure the bleed screw at the injection pump is closed. If that bleed screw is open it can affect the operation of the engine running as well.

 

[thepumpguysc]

That lift pump should SQUIRT.. not ooze.. I think you found your problem..
Pull the line off the tank & make sure its flowing good to the filter.. first
Then replace the lift pump. Bleed the line at the injection pump, loosen the inlet bolt and spin the engine until you have fuel there, NO AIR.
retighten, loosen the 4 lines AT the injectors and spin the engine until fuel squirts out, retighten and off you go..
Let us know how it worked out..

 

[willie59]

Accessing the fuel line connection to the tank on an F or G series Bobcat can be a PITA, I wouldn't go there unless I just had to, that's why I suggested dropping a hose into a fuel can for preliminary troubleshooting

 

[thepumpguysc]

You might be right willey.. I guess he could pull the inlet line AT the filter to see if it flowing.. TO THE lift pump..
Good call.. I wouldn't want to pull a tank if I didn't have to..
AS LONG AS your getting a good stream TO THE FILTER, that's all that matters.. Then MAKE SURE your getting a good flow TO the lift pump.. OUT OF the filter to the lift pump.. Then the lift pump takes over and pressurizes the fuel TO the injection pump..
In other words> its gravity to the filter and suction after the filter, from the lift pump, then pressure from the LP to the inj. pump..
I hope this didn't confuse you..

 

[willie59]

Well that's the idea, we need to determine if it's a fuel tank issue, supply line issue, lift pump or injection pump. By connecting a hose from a fuel can to the lift pump we both eliminate the fuel tank for now and focus solely on the lift pump and injection pump. Now we determine if the engine responds properly or not. I try to find simple/easy ways to do a task that yields good results. BTW, don't forget to check that bleeder screw is closed on the injection pump return line.

 

[thepumpguysc]

YUP, as long as he puts the line from his can on the INLET/suction side of the lift pump, he'll be doing good..
Good call..