is this B7100 running okay?

   / is this B7100 running okay? #1  

grossgary

Silver Member
Joined
Jun 11, 2008
Messages
237
Location
midatlantic
Tractor
1994 Kubota B7100 HST 4WD
I picked up my first tractor the other week - a 1994 B7100 HST 4WD with 1700 hours. Replaced HST filter, fuel and air filter, changed oil, greased fittings. Being my first tractor and first diesel i'm not sure if these things are normal or not:

Black puff of smoke on start up, but none afterwards.

When mowing with a 60" MMM, full throttle, in high range it seems to lack power up small hills. It starts to slow down even up a slight grade. I didn't expect it to slow down going up that very slight grade. When it starts to bog down some black smoke will come out of the exhaust and goes away quickly as the engine speed picks back up - normal or a sign of something wrong (other than just bogged down!)?

All in all it's working fantastic, i love the tractor and this minor thing won't bother me at all. Just curious what this sounds like.
 
   / is this B7100 running okay? #2  
Congrats on your purchase! These are great little tractors.

grossgary said:
Black puff of smoke on start up, but none afterwards.
normal

grossgary said:
When it starts to bog down some black smoke will come out of the exhaust and goes away quickly as the engine speed picks back up - normal or a sign of something wrong (other than just bogged down!)?
This is normal, the black smoke is a result of the governor dumping in fuel trying to keep rpm's up.

I can't comment on the slowing down as I do not have an HST. Perhaps someone else who does can jump in here.

Charles
 
   / is this B7100 running okay? #3  
The black smoke is typical of any diesel that is not working at an optimum power setting for the work being done. Trying to remember if I mowed mid or hi range with my 7100, but I know in heavier going with the subsequent and current 8200, mid range it has to be. My son likes hi, but it doesn't do as good a job and he looks like he's on a motocross bike with our bumpy lawn. My 4330 and my neigbor's L-48 both bog down on pavement going up some of our hills. In general, my sense is that hi range is really just a flat going transport gear with a few exceptions. The smoke is a good indicator of when you are asking too much. In terms of hours, assuming reasonable maintenance, 1700 hrs is nothing for a Kubota diesel, so it is unlikely that it is tired to the point of significant power loss. My dealer has told me about various boatmounted Kubota diesels with tens of thousands of hours on them. And another discussion this morning mentions a JD4020 and a Steiger with similar amounts of hours. Diesels are just flat amazing.
 
   / is this B7100 running okay?
  • Thread Starter
#4  
great information guys and i'm glad to hear that's normal.

okay - high gear with a 60" MMM is probably the answer. not a problem for me at all, it doesn't even slow me down really since it's just a very short stretch i'm trying to maintain those high speeds...not even 50 yards.

i was worried it indicated something was wrong with it, needed more tune up items, etc. thanks all!
 
   / is this B7100 running okay? #5  
grossgary said:
great information guys and i'm glad to hear that's normal.

okay - high gear with a 60" MMM is probably the answer. not a problem for me at all, it doesn't even slow me down really since it's just a very short stretch i'm trying to maintain those high speeds...not even 50 yards.

i was worried it indicated something was wrong with it, needed more tune up items, etc. thanks all!

Everything you've described sounds pretty normal to me. High range and a fully depressed HST peddle is pretty much for down hill or level ground only, at least that痴 my experience. While you are mowing you can probably leave it in High but not fully depress the HST. Remember the HST is like a variable transmission not an accelerator. The tractor will have the most power (wheel torque) at high throttle and just barley depressing the HST. The more the treadle is depressed the higher the "gear."

I'm sure you'll love the little tractor, for 16 little horse power it will do amazing thing.
 
   / is this B7100 running okay? #6  
Trying to remember if I mowed mid or hi range with my 7100

Did you have a B7100 with a 3 range HST? I didn't think they made such. I had 1995 B7100 with a 2 range HST, no finish mower, but did use a 4' Bush Hog rotary cutter. I used High range some on level ground with light grass to mow in my pasture, but low range for any slopes. So, yep, grossgary's experience sounds normal to me.
 
 
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