Workmaster 35 can't throttle up

[miketx55]

Hi all,
My 2013 Workmaster 35 is having running issues. It will start and idle, but if I throttle up, it struggles. I've checked the fuel line to the tank for problems (none), and replaced the fuel filter, but it still has problems. However, when I tried to bleed the fuel filter via the manual pump on the top of the filter housing, nothing comes out of the bleed screw, no matter how many times I push the pump. I can hear air being pushed out of the bleed screw. Some fuel must be getting through since the engine does run. If I let the tractor sit for 15 mins "off", and then start it, I can rev it up to full throttle (2700-2800 rpms), but after 30 secs it dies down to about 1000 rpm and stumbles around that range. It definitely seems like a lack of fuel.
Question: is the manual pump knob on the filter housing supposed to "close" (pushed down position) while running? I noticed it slowly closes (~ 1 min) after starting the tractor.....just about the time that the problems start. However, after sitting for a while not running, the knob slowly eases back to the up position. Maybe this is how it is supposed to work, but I can't find anything about it in the service manual. I'm curious if the filter housing pump has a problem or clog, slowing the fuel down.

Mike

 

[RustyA]

Have you tried running it without the fuel cap fully closed? Perhaps cap vent is restricted ?

 

[miketx55]

Yes....the tank has a very basic fuel cap (ie not restrictive). Besides, the tank has a vent hose also.

 

[ruffdog]

Maybe the hand pump is bleeding air into the fuel supply.

 

[miketx55]

Yeah, something weird like that appears to be happening. I plan to bypass the filter (with external filter) in a few days to test if the filter housing is causing issues.

 

[Jerry/MT]

Hi all,
My 2013 Workmaster 35 is having running issues. It will start and idle, but if I throttle up, it struggles. I've checked the fuel line to the tank for problems (none), and replaced the fuel filter, but it still has problems. However, when I tried to bleed the fuel filter via the manual pump on the top of the filter housing, nothing comes out of the bleed screw, no matter how many times I push the pump. I can hear air being pushed out of the bleed screw. Some fuel must be getting through since the engine does run. If I let the tractor sit for 15 mins "off", and then start it, I can rev it up to full throttle (2700-2800 rpms), but after 30 secs it dies down to about 1000 rpm and stumbles around that range. It definitely seems like a lack of fuel.
Question: is the manual pump knob on the filter housing supposed to "close" (pushed down position) while running? I noticed it slowly closes (~ 1 min) after starting the tractor.....just about the time that the problems start. However, after sitting for a while not running, the knob slowly eases back to the up position. Maybe this is how it is supposed to work, but I can't find anything about it in the service manual. I'm curious if the filter housing pump has a problem or clog, slowing the fuel down.

Mike

Do you have an operator's manual for your machine? If you do, read the fuel system description on how it's supposed to work. If you don't have one, get one and learn how your tractor is supposed to work and how to operate it. The Tier IV tractors have emission controls that can cause all sorts of problems with operability.
I have long since stopped trying to help with these kind of complaints because these systems are so complicated that even the service departments at the dealerships need computerized testing programs to trouble shoot them.

Your problem appears to be caused by a lack of fuel supply and about all you can do is replace the filter, make sure that the fuel circuit between the tank and the fuel injector is un-interupted by mechanical blockages (dirt, bugs, etc) water in the fuel, and remove those. After that, it's the dealers diagnostic program.

 

[RjCorazza]

Don't know about your primer on the filter, but my aftermarket filter primer needs to be pushed down and threaded closed when done.

 

[miketx55]

FYI, I bypassed the filter/housing with a simple lawn mower fuel filter (all I had to test with), and she runs great now. So yes, there is a blockage and it appears to be within the filter housing itself.
This is a 2013, so not quite as complex as newer tractors. And yes, I have the operators manual and service manual. I have repaired/replaced many other items on this tractor, including the hydraulic pump. I also have a JD 950 tractor.

 

[dlctcg]

@miketx55 - I don't know your Workmaster 35 as well as other NH tractors, however if your system has a fuel return line at the filter housing that runs back to the tank... I would check that line. If it has a blockage or has collapsed it could cause a fuel delivery problem at the filter housing.

I've had it happen on a couple of the TC tractors... If you do have that return line there are a couple of ways to test it..