John Deere CT322 Rough Low Idle

[rmj]

When I first start the machine, it runs smooth, but after about 2 minutes the low idle is sort of rough. Increasing the low idle speed only slightly smooths it out. It is only at low idle that I have the problem. I visited the local JD dealer and he said that some machines will have a rough low idle and not to be concerned as long as it smooths out when increasing the speed. He said it is probably the computer. I do not have any codes on the display. Things I have done: changed both fuel filters, checked fuel vent line, drained fuel tank and put in new fuel, Any ideas would be appreciated. Thanks

 

[Bobcatdan]

Computer does nothing with that engine. There is a check valve on the back of the engine in the fitting for the return hose. Those go bad and it can't hold fuel pressure. Also check oil level to make sure it isn't rising. A injector pump may have locked up, they normally run pretty smooth for a dead miss.