I think my 1572 is jealous of the new 1772

[FrankF3]

So, I got my new 1772 about 3 weeks ago. It is running well and I am just getting to the point of getting ready to mow with it. I think my 1572 is getting jealous and starting to throw fits. My wife said after I was done mowing that it behaved the same way for her the week before but she forgot to tell me about it and with this episode she said she sees a pattern developing.
I have a decent sized yard to mow, a little over 2 acres. Well the 1572 runs fine for the first hour and a half or so, then I swear the engine slows down a bit, first unnoticeable then more drastically. After it starts behaving this way, the fits happen more often in frequency. Basically, the engine slows right down as if it has no fuel, if I stop the forward motion with the tractor, sometimes it gradually recovers engine speed, sometimes is does not and the engine stalls. Sometimes after stopping going forward, and trying to recover I will disengage the deck. Sometimes this is enough, on several occasions the engine starts belching heavy black smoke while recovering and I can smell raw diesel with the exhaust.

The strainer in the tank, and all the filters were replaced within the last 2 months. Since I had the problem with the algae with one of my diesels, they all drink form the same tank that has been treated with biocide. What does this sound like to you. I am looking for any and all suggestions. Could it be the injection pump on the way out? If so, what are typical symptoms of a bad injector pump?

[Sam Mac]

Generally black smoke from a diesel is caused by, lack of air, too much fuel or lugging.

[FrankF3]

On the 2- 3 times when it was sitting there, running at 1/4 to 1/2 speed, the hydro was set to neutral so there was no forward or backward and the deck was off. I remember 1 time in particular as it was happenning , being puzzled wondering where do yuo start to diagnose this. The engine when being restarted, spins over normally and does not turn over slow as if something is binding. It's either too much fuel or like you said Sam, not enough air.

[Sam Mac]

When was the last time you checked the air cleaner and the screen?

[FrankF3]

Every spring before I start for the season, it get a new air cleaner whether it needs one or not and everything is all cleaned out. My wife said it start out running fine but after an hour to an hour and a half, the trouble starts. If I wasn't getting fuel, I could explain the loss of power and slower engine speeds, but when it starts belching out black smoke, there's too much fuel to burn. I'm going to have to see if I can find a Kubota D600 Engine workshop manual for reference. If I remember correctly there was a troubleshooting section in it. However it was like using the shotgun approach in that you will eventually find the problem byt replacing lots of parts.

[Sam Mac]

Link for the Bota service manual.

http://www.onlycubcadets.net/forum/s...ead.php?t=4660