G1800 engine power loss

[bstauss]

I was running my G1800 at full throttle, sitting still, and the engine suddenly slowed up like it was under a heavy load or not getting enough fuel. I backed the throttle off, which seemed to help, and pushed it back to full. It seemed normal. It did the same thing again but under load. I was mowing some heavy grass 8-10 inches high, and moving at maybe 2/3 speed. Engine acted like under too much load or not enough fuel. I slowed my forward speed, engine recovered. Sped up and it did it again.

I just bought the tractor used with 800 hrs, seems to have been well maintained. Both fuel filters are new. Engine starts immediately after glow plug light goes off. I am still learning about diesels and have no clue why it is doing this. It was fine the rest of the two hours I mowed if I didn't push it. I know it's only a 16hp engine and a 1000 lb tractor, but surely Kubota sized the engine to handle the grass cutting load I gave it.

Would really appreciate some help on what the check next. Thank you.

 

[Dave_eng]

Fuel deliver is the first issue to verify.

I believe you have an electric fuel pump.

Often this pump is referred to as a lift pump because under some circumstances related to fuel tank level and the slope or lack of slope on the ground you are operating on, gravity can supply fuel to the injection pump.

Low fuel tank levels or driving up a hill can stop the delivery of fuel by gravity and the lift pump is needed.

Check that your lift pump is delivering a solid stream of fuel any time the key is ON. Open a line at the filter to observe.

Dave

 

[bstauss]

I'll try that Dave. Thank you. I was on level ground and had maybe 1/3 tank of fuel. It is an electric fuel pump.

 

[lugbolt]

either the fuel pump is not getting good electrical signal, or the fuel tank has a restriction inside of it. I ran into both of those issues. Also had one electric pump fail when I had mine. You can use a cheap parts store chincanese pump if you want but they don't last. I ended up going back to a Kubota pump, and they ARE pricey (but high quality). It was working perfectly fine when I sold the mower.

At one point I also had a turbo on it and messed with the pump a little, little more demand on the electric pump, lines, hoses, tank. The kubota pump kept up just fine although I couldn't really tell much of a power increase with the turbo @ 5 psi max. EGT got on up there (no intercooler), probably needed some timing adjustment among other things. Pulled the turbo off and sold it separately. Really not worth the hassle.

Do a no load fuel flow test by pulling the fuel line off of the engine, and putting the open end into a container so that you can see how it flows. Then turn the key on and watch the flow rate. It should stay steady. Typically when there is a problem with flow, you will see it come out good initially and then slow down.

One other thing to look at is the metal fuel line on the frame. Iv'e seen them bent up pinched mashed etc.

 

[Murrstir]

I was running my G1800 at full throttle, sitting still, and the engine suddenly slowed up like it was under a heavy load or not getting enough fuel. I backed the throttle off, which seemed to help, and pushed it back to full.

Hi all,
Having much the same problem with my F3060 the other day, I read this thread for clues. In my case she also was also making some unusual chattering/knocking engine noises, making me initially fear a broken piston crank or worse. After all, it is 2020. Among other things I checked was the rust covered exhaust system, and found a hole in the bottom of the muffler cylinder. Disassembled that and off to town for repair at my favorite welding shop. Re-installed it along with a new gasket and the noise problem was abated but not the power loss. My problem was a combination of poor fuel clogging the little paper filters and a leaking fuel supply line. Once I replaced a short bit of stressed fuel line, the two filters and added diesel conditioner to the tank, she is running very well again, and a bit quieter too. I think the aged fuel line allowed our fresh Belizean air to enter the combustion process when under load. I hope she will now run longer on a tank up as well. Good luck. Please let us know what solves your problem in the end.

 

[bstauss]

Resurrecting my post here from last year. Have had the tractor stored due to a mower deck issue which is now resolved. Took it out to cut the grass today. Ran perfect for over an hour, then acted up as described in my original post. On a couple of occasions it almost stalled, no load on engine. I went ahead and put it away in the shed as we all know there is no transmission release to roll/free wheel these beasts. I'm going to start by testing the fuel flow at the engine and may go ahead and just replace the two fuel filters as they are inexpensive. Will post what I find, and any additional feedback appreciated.

 

[peteweb]

I have just run into a similar problem. I checked the two fuel filters, The one before the pump on the tank side , just below the levers on the righthand side, appears to have over 50% air in it . The mower starts so obviously gets enough fuel to start, but is running rough and has lost power. Has anyone else encountered this problem?
Why would all that air be in the pre pump filter? I am not sure how to go about bleeding the air out. Any suggestions greatly appreciated

 

[lugbolt]

I have just run into a similar problem. I checked the two fuel filters, The one before the pump on the tank side , just below the levers on the righthand side, appears to have over 50% air in it . The mower starts so obviously gets enough fuel to start, but is running rough and has lost power. Has anyone else encountered this problem?
Why would all that air be in the pre pump filter? I am not sure how to go about bleeding the air out. Any suggestions greatly appreciated

don't worry about the air in the filter that's normal

but that filter catches a lot of junk, if you ain't already, replace it.

while you're replacing the filters, see how the rear line that comes out of the tank is flowing. It should gush out! If it's just a trickle, the tank has something inside of it plugging the outlet.

 

[Mark_BX25D]

Loss of power on a diesel is usually a fuel problem. Possibly an air flow problem. Lastly, a lack of compression. That's the one you don't want to hear.

Fuel is the first place to look. The could be clogs (filters, tank, lines) or pumps failing.