2021 X1.35 with the Kukje engine.

[Sheepacres]

I have a McCormick X1.35 that will not start on low idle, meaning I have to raise the idle lever so that when it does start, it starts at 1500-2000 RPMs range. I thought it could be the electric fuel lift feed pump, so I replaced it with a new one, and it is still doing the same thing. In operation, you have to constantly adjust the throttle lever to meet the load, whether it's a load with the bucket or using the PTO. It will bring the idle down under load. If you are just traveling up an incline with just the tractor, you need to raise the RPM, but when you come down the incline, your RPMS will race to 3000 +. Any suggestions on what to try?

 

[bmaverick]

I have a McCormick X1.35 that will not start on low idle, meaning I have to raise the idle lever so that when it does start, it starts at 1500-2000 RPMs range. I thought it could be the electric fuel lift feed pump, so I replaced it with a new one, and it is still doing the same thing. In operation, you have to constantly adjust the throttle lever to meet the load, whether it's a load with the bucket or using the PTO. It will bring the idle down under load. If you are just traveling up an incline with just the tractor, you need to raise the RPM, but when you come down the incline, your RPMS will race to 3000 +. Any suggestions on what to try?

Kukje is now owned by tractor manufacture TYM.

Is there a governor on the main fuel pump? On these diesel engines, it serves to maintain the idle needed as well.

Kukje has been a Yanmar parts supplier for over 60 years. And Yanmar has licensed their engine tech to Kukje. It's possible your McCormick has a combo engine and related to a Yanmar 4TNV__ engine.
4-cylinder, 2.0L built by Kukje

 

[tacticalturnip]

Try cross-posting this in the TYM section, it's basically a Branson/TYM 3620.