I have a Hustler Super Z with a Kohler Command Pro EFI 33HP model ECV880. It is only 5 years old with under 200 hours and very well taken care of. Since it was brand new, it was always a little slow to fully throttle up under load. I could go full throttle, engage the PTO and then maybe 5 seconds later I could hear the RPMs come up and hit the sweet spot RPM range to mow. Over the past few months it has gotten worse. In fact, lately, it has left me a few times when, no matter what I did, I could not get it to throttle up all the way and was not able to mow. It seems to be worse at the engine gets warmed up. My neighbor has the same exact mower, 3 weeks older, and hers is doing the same thing but not quite as bad. I have fresh oil, both air filters new, new plugs, changed the fuel filter and vacuum fuel pump and all hoses just to be sure. Still doing it. I am stumped. Throttle position sensor? I thought about maybe an injector but I always run good, non ethanol gas. Even added a little fuel injector to the tank just to be sure. I am at a complete loss at what it may be and its driving me absolutely CRAZY! If anyone can suggest a solution or has seen this before, please let me know. Thanks again, Jesse in Florida.
Does it run rich and blow out black smoke? You can keep throwing parts at it or take it to a dealer that has the kohler soft ware and can read the codes and pin point the problem.
Hi and thank you the reply. No, the mower does not run rich and blow out black smoke. It runs nicely, very evenly but it just does not want to get to full throttle very easily. It seems to be a little worse when it has been operating for a 1/2 hour or more. The warranty just expired 4 weeks ago so I am frustrated that I did not think to get it in before that ran out. It may be my only option. My neighbor has an identical mower, that is why I bought mine, and has the same exact issue but hers is not quite as bad. The throttle linkage looks to be just fine as it is rotating and engaging everything to the max. Usually this hesitancy to go full throttle is when I turn on the PTO but this last week I noticed, for the first time, that it was doing the same thing when the blades were not in motion. I will try and take it in next week. Thanks again.
