2019 JD X739 skipping/surging/post ignition

usernametaken · Jun 19, 2025

So, my 2019 X739 has been flawless since new. A hair over 100 hours on the clock. Today as I finished up mowing, I noticed that it wasn't smooth at full speed as I drove back to the barn. Played with it a little and noticed a strong skip and RPMs wouldn't go to full on the gauge. Drove it into the garage and when I went to shut it down, it kept running as if it had post ignition / dieseling. Had to get the rpms up and try a could have times to get it to finally shut down. Pulled the air cleaner and there is a strong gurgling / percolating sound like fuel boiling. Anyone have a clue as to where to start? Dealers are so far out on service and I need this thing weekly with no backup mower on site. Thanks in advance. Link to the gurgling after shut down below.

oldnslo · Jun 19, 2025

Is that an air cooled or water cooled Kawasaki engine? In theory water cooled should be more consistent temperature as long as radiator is not plugged with chaff. If like my X540 it collects chaff on radiator screen and around the cylinder heads. I blow it off every couple of uses or more in dusty conditions.

If air cooled are all the cooling fins clean allowing air flow across the heads and around the intake carb area? If these are partially blocked it could engine to run hotter.

usernametaken · Jun 19, 2025

Water cooled. EFI not carb. I think I may have found a possible issue. I'm thinking an injector was stuck open on one cylinder. That would explain the post ignition after the key is off and the boiling fuel sound once it's shut down. I also found one plug was very fouled and one was clean. So, I cleaned the bad one, reseated the injector plugs, reseated a couple other EFI harness connections and what do you know. Ran perfect. Got it back up to temp, shut it down. No post ignition and no gurgling after shut down. Simple solution always seem like voodoo cures to me but hopefully it stays fixed. If not, I'll look at swapping the injector on the side with the fouled plug...