variable rpms above 2000 rpm on Kubota L3800

[bobmart]

My 4 year old L3800 Kubota has recently started to lose power above 2000 rpm. The rpms will cycle up and down by 100 rpm at a 2300 rpm setting necessary to run the pto at 540 rpm. I think its due to either 1) bad fuel, or 2) clogged air filter. I can't find my manual and Kubota's website does not allow you to order a new manual. So, I don't know how to change the fuel filter. But I don't see any water in the bottom of the fuel filter bowl. Any ideas?

 

[Fallon]

Change your fuel filter & clean or change your air filter. Those are the likely cause & easiest things to do.

If your fuel filter is plugged with dirt & what not, why would there be water in the bowl?

http://www.kubotabooks.com/AutoIndex/index.php?dir=Tractor Owners Manuals/

I didn't see a L3800 manual there, but I'm sure more than 95% or more of my L3200 is the same as your L3800. Not sure if its the same engine with turned up injectors, or a slightly different engine, but I bet the fuel filter is the same.

 

[bobmart]

Change your fuel filter & clean or change your air filter. Those are the likely cause & easiest things to do.

If your fuel filter is plugged with dirt & what not, why would there be water in the bowl?

Index of Kubotabooks/Tractor Owners Manuals/

I didn't see a L3800 manual there, but I'm sure more than 95% or more of my L3200 is the same as your L3800. Not sure if its the same engine with turned up injectors, or a slightly different engine, but I bet the fuel filter is the same.

Thanks Fallon. Sorry it took so long to respond. I was doing the maintenance and changing out the box blade for the rototiller for another tractor job tomorrow. the replacement air cleaner fixed the problem. Now plenty of power and constant high rpm. The radiator overflow was almost empty and the screen in front of the radiator was half clogged up (at 130 hours). I need to do maintenance more often. I started doing small lot (one-half to 2 acres) tractor jobs last year for extra income and now get about 2 jobs a week. Only 6 more payments and the loan with Kubota Credit Corp is paid off.

 

[Fallon]

Slow? That's usually measured in days, not hours.

I need to clean the radiator screen daily or more often when mowing. Its easy, so check it every time.

Keep up on the maintenance & it should last a long time.

 

[teg]

I would also blow air through the radiator from the back side, the screen only stops so much.

 

[DieselAntics]

Wanted to bring this thread back to the surface due to my L3800 having the same issue with fluctuating RPM’s.

Right above the oil fill cap is a fuel shutoff valve. Mine evidently vibrated to almost a closed position which was starving the tractor of fuel. Opened back up all the way and zero problems since. Just wanted to throw that out there if anyone else is having this issue. Check that shutoff valve before you go throwing parts at it.

Thanks,
Drew