# B21 Losing Power



## jjw (Feb 16, 2021)

My Kubota B21 lose power when under load. The engine runs great at full throttle with no problem. When I drive on flat ground it runs pretty with the pedal all the way down. As soon as a hill is introduced it loses power and I have to let off to half pedal. Forget it if I try to use the loader and drive up hill at the same time, it will completely bog down.
We have done all the basics. new air filter, new fuel filter, new oil filters, Check the fuel line that's its pumping good. Nothing is in the fuel tank. Even had the fuel injectors rebuilt. 
Any help or suggestions on what or where to look next would be greatly appreciated.


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## thepumpguysc (Jan 25, 2015)

Make sure the throttle is going all the way open, stop screw to stop screw.
(Hi idle/low idle)
Make sure your getting all the rpm’s that r required..
The run/stop solenoid is also a place to look for interference..
Do all your tests w the air cleaner REMOVED..
Good luck.


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## BenHeno (Nov 9, 2021)

I have the exact same issue. Any update about your repairs? Had you resolve your issue? Thanks


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## augwest2657 (12 mo ago)

jjw said:


> My Kubota B21 lose power when under load. The engine runs great at full throttle with no problem. When I drive on flat ground it runs pretty with the pedal all the way down. As soon as a hill is introduced it loses power and I have to let off to half pedal. Forget it if I try to use the loader and drive up hill at the same time, it will completely bog down.
> We have done all the basics. new air filter, new fuel filter, new oil filters, Check the fuel line that's its pumping good. Nothing is in the fuel tank. Even had the fuel injectors rebuilt.
> Any help or suggestions on what or where to look next would be greatly appreciated.


I had very similar issues with my b7500 tried everything except the injectors, it turned out the fuel filter holder was cracked. Hope this helps


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