B2320 Won't maintain RPM Mowing

   / B2320 Won't maintain RPM Mowing #1  

Farmall45b

Silver Member
Joined
Sep 18, 2008
Messages
203
Location
White Bear Lake, Minnesota
Tractor
2014 Kubota B2650 HSD Cab
Ran into a problem when flail mowing last night and thought I would see what the TBN community has to say. My B2320HST with 215 hrs. had trouble maintaining full 540 PTO rpm when I was running my flail mower last night. It seemed to drop rpms in the longer grass more than it used to and take longer to recover the full rpms again. The flails on the mower are near or already past the end of their life, so maybe the flails are just beating the grass rather than cutting it? The fuel and air filters are new about 20 hours ago and look clean yet. The fuel I had in the tractor may still have been a winter blend, I am not sure how much of an effect this would have on the problem. I did buy some new fuel, as the tractor is almost empty after mowing. What are everyone's opinions or suggestions?
 
   / B2320 Won't maintain RPM Mowing #2  
Do you have a slip clutch? I can't tell how you're measuring the PTO RPM. If it's really dropping at the PTO shaft coming out of the tractor that's one thing, but if it's losing RPM downstream of a slip clutch, it could just mean the slip clutch is slipping.
 
   / B2320 Won't maintain RPM Mowing
  • Thread Starter
#3  
No slip clutch, I am noticing the RPMs dropping of on the tachometer.
 
   / B2320 Won't maintain RPM Mowing #4  
need a bigger tractor
 
   / B2320 Won't maintain RPM Mowing #5  
Check your air filter and at the same clean the screen in front of the radiator.
 
   / B2320 Won't maintain RPM Mowing #6  
jokergerm said:
need a bigger tractor

That's not productive!

When you say the RPM's drop more then they used to...where you mowing the same field under the same conditions (wet/dry grass 12" high) or did the conditions change?
 
   / B2320 Won't maintain RPM Mowing #7  
How big of flail mower are you running? You have 17 HP at the pto and flails take some horse power to run. I doubt anything is wrong with your tractor. I would look at the mower. Change out the gear oil in the top and side gearcase to a lighter weight. Say a 75-90 synthetic. That might help a little. If your knives are dull they are tearing instead of cutting that might be your whole issue. Imagine trying to cut a rope with a butter knife instead of a hunting knife. Requires a lot more force and now your engine is trying to cut the grass with a butter knife.
 
   / B2320 Won't maintain RPM Mowing #8  
Check your air filter and at the same clean the screen in front of the radiator.

X2, plus your fuel filter and finally, question the fuel quality itself. If you've never faced this issue before, under same circumstances, then your D1005 engine might not be operating the same as it has in the past. Worth checking, that's for sure. I'm confident you know what is "normal" for your machine and right now? It seems to be surprising you with lower power for some reason.
 
   / B2320 Won't maintain RPM Mowing #9  
If you have clean filters all around then I bet it is your mower. Dull knives take more HP and the mower will not clear the grass as well and this would give you the delayed rpm recovery. If your blades are shot I would replace them first and see how things respond before I worried to much about the tractor.:thumbsup:
 
   / B2320 Won't maintain RPM Mowing #10  
No slip clutch, I am noticing the RPMs dropping of on the tachometer.

Just to clarify, your original post said you "had trouble maintaining full 540 PTO rpm", but you would not see 540rpm on your tachometer. So are you saying that your tachometer normally shows something like 2500rpm when you're mowing, but lately it drops to something like 2000rpm and won't run any faster?
 

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