Kubota ZTR power lose

[mchild]

I have a Kubota ZD21 diesel zero turn mower that has progressively been getting worse about having periodic power loses. It normally does not happen unless I have been cutting for a while and when it does, it will not stop running altogether, but the engine speed will fall way off and only recover over a period of a minute or two. Once it starts this it can happen several times in a short period of time. I disengage the blades and sit still while waiting for the engine to recover its speed and power.

The air and fuel filters only have about 30 hours of use. Does anyone have an idea as to what I should be checking?

Many thanks,

Mark

 

[SkyPup]

Definitely change the air and fuel filters even if you think they are good.

Does it emit black smoke, like it is under heavy load, during the "off-power" moments?

Are you certain that the belt on the deck is in the pulley track and not rubbing on anything? Likewise, are the blades underneath the housing turning freely?

The reason I ask is that it will be emitting black smoke only under heavy load when the fuel delivery is too rich for the given rpm, this would indicate a clogged air filter or a large amount of friction somewhere. Fuel filter stalling would most likely not be emitting black smoke.

How about the transmission, is it functioning normal?

 

[mchild]

Skypup,

Thanks for your response. When it loses power it doesn't do anything other than drop in power. There is no smoke and everything seems to work just fine except it does not have much power - about like idle and it runs smoothly. Blades turn with ease and the transmission is working as it is supposed to. In fact, it has even lost power while the equipment isn't moving.

After making my initial post, I did change the fuel filter but I have not been able to run it long enough to see if it made any difference. It normally takes an hour or more before it happens.

Mark

 

[pemad]

Sounds like water in the fuel. Had the same problem with my BX2200. Replaced fuel filter and put in a fuel additaive. Ran like a champ after that.

 

[wushaw]

Sounds like fuel delivery, not enough, sucking air, something clogging the tank/lines.

 

[SkyPup]

Yes, I agree with the others, it is not a rich problem. Sounds more like a fuel delivery problem. Hopefully the new fuel filter does the trick.

Sometimes all it takes is one bad tank of fuel to completely clog the fuel filter if the diesel fuel has had water in it and bacteria, fungus, and algae are growing in it.

Our ZD-21 has over 300 hours on it and it is only two years old now, it has been performing flawlessly with zero problems. I really enjoy it, very powerful, quiet and fuel economical. It is amazing the amount of mowing you can do on it with a pittance of diesel fuel....

 

[Nasty135]

mchild,
I had rented a small kubota powered track loader a few years ago, and while it was a great little unit and did all I needed it to do, it had what sounds like a very similar problem that you are talking about... It would run great for awhile then it would just die, however it would always restart immediately and maybe chug a couple seconds then take off like nothing was wrong.. water in fuel sounds like a possible cause at least to me.

 

[TimFisher]

Mine did the same thing, I replace the fuel filters to no avail. There was a blockage in my fuel line from the tank to the primary fuel filter. Once the hose was removed from the pre-filter and compressed air applied going back into the tank, the problem ceased. Runs like a champ again.