Hard to start kubota

[sherpa]

I have a B20 kubota 20hp and it is hard to start when already warm. I can use it for an hour, turn it off for 3 mins and I have to use the preheat to get it started again. (I always preheat when cold starting). Also when it gets real hot it loses some power. Most people would not notice the loss of power unless they were using the tractor a lot. Its only noticable when you are driving it (HST) It works fine sitting still using the backhoe. It is in the engine not the HST, I can tell that. Its got about 1400 hrs on it and most of the time runs OK. I have only had it the last year and put 100 hrs on it. What do you think could be the problem? I thought about the injectors which I know nothing about. Are they hard to service? I heard they were expensive to buy. Is there something else I should look at?
Mtnman

 

[Deerlope]

Check the fuel filter. If it is getting real dirty it will be sluggish when trying to bring it up to full RPM's. The injectors should not be going south yet with only 1400 hrs. Normally they are not serviceable by the DIY'er. Could also be the injector pump or even a fuel pump. Some of the more knowledgable guys will chime in I am sure.

 

[Soundguy]

Fuel / air filters.. and at very worst... low compression.

Soundguy

 

[sherpa]

I already had the fuel filter out and it looked OK. I saw in the manual something about adjusting the pump, whats that all about? I just have started too many other tractors and I know mine is not right.
Sherpa

 

[sherpa]

What about valves, do they need adjusting?
sherpa

 

[mark777]

Sherpa,
That is exactly what I was thinking. I don't know the scheduled maintenace for your tractor, but mine is adjust (or check) valves every 300 hours. Often valve adjustments are let go or overlooked by many....and it would be the first thing I would try.
Good luck, Mark

 

[sherpa]

Is checking & adjusting the valves something I could do myself? I done it on motorcycles.
Sherpa

 

[v8dave]

</font><font color="blue" class="small">( I already had the fuel filter out and it looked OK. I saw in the manual something about adjusting the pump, whats that all about? I just have started too many other tractors and I know mine is not right.
Sherpa )</font>

You don't say if you have changed the filters or fluids since you bought the tractor. If not, don't look at filters, just replace them. Also, other threads I've read here say hydrostatic fluid that has been overheated may exhibit some of the loss of power symptoms you describe.

Another thing could be debris in the fuel tank blocking the outlet. Take a good flashlight and peer into the tank. Any debris makes the tank suspect. Now on my Kubota I can't see into the tank body from the filler, so this wouldn't be much help. If that is your case too, take a length of hose and a suction bulb and suck a bit of fuel from the tank--make sure the hose bottoms out in the tank. Squirt the sucked out fuel into a jar to look for junk.

One of my mechanic friends says "always trouble shoot the cheap and easy stuff first". Darned if he hasn't been right. I ran out of gas in one of my old cars (idling in the driveway after sitting awhile) and after dismounting and checking the fuel pump and carburetor, I found the tank empty. I'm a slow learner sometimes, I had to repeat this trick on a second car before the logic sank in.

 

[sherpa]

v8dave
I changed the filters last year when I got it but not the fluid. I guess I will get that done.

As far as fuel, that may have been part of the power problem. About a week ago I was cleaning the fuel filter and could not turn the fuel off with the pitcock. It would turn but loosely. After clamping the fuel line off and getting it all apart I found the pitcock lever had broken off the little hump inside that fits into the plastic cut off valve. I also found that the plastic cut off valve was partialy close. I made all these repairs and so far its doing OK buts its not got hot enough or strained it to tell if this actually cured the power problem.

I got the valves adjusted last night, it was easy after I figured out which cyl was number one. Its a lot quiter now but still hard to start in my opinion compared to other tractors I have started.

What about fuel injectors? Or is there something else I could look at thats keeping it from starting easy?
Sherpa

 

[SkyPup]

Your injectors may be coked pretty good by now.

Try some Lubro MolyDiesel Purge injector cleaner. It is the strongest and best diesel injector and nozzle cleaner available. Just follow the directions on the container and use it full strength, ie undiluted.