Mxu500i rev limiter

[spudit]

Hi all.  I have just purchased a mxu500i which has an issue that hopefully some on this group can help solve.  It currently will only rev to 3400rpm app.  Quad has 10000kms.  Recently had new fuel pump and service.  Since this problem occurred I have tested tps,and other sensors with no faults found.  I have also introduced fuel into the throttle body via an atomiser spray bottle but it still doesn’t rev pas 3400rpm.  I also have installed a timing light and spark appears to be constant.   I have been unable to have ecu tested or swapped with another know working unit. Appreciate any help.  Thanks Michael

[spudit]

It’s a 2011 model

[Bratman2]

Check limit screw at throttle. May have been used by a younger driver so parent screwed limit screw in. It is on the front side of the thumb throttle. Turn out one full turn and see if you gain rpm. If you do continue until you get the rpm it should do, 7k-7.5k.

[spudit]

Hi.  Yes. Limit screw is fully backed off.  Engine hits around 3400 rpm at about half throttle then does nothing else whilst opening to full.  Got me buggered atm.  Thanks for your reply. 

[Bratman2]

Weird, I had high hopes for the screw limiter. My zero turn mower just did the same thing. It is suppose to run around 3400 rpm. It dropped back to maybe 2500 rpm max. Keeper for the throttle cable broke. The keeper doesn't allow the outside cover of the cable to move. Had to replace it and now everything is good. I don't know if your MXU cable is the same but it is mighty ironic that just happened to me. So check both ends of your throttle cable!

Good luck!!
Glenn

[spudit]

Throttle is opening 100%.  Just no difference from about 50%.   I am trying to find someone that owns a 500 so I can send my ecu to try 🤞

[spudit]

Hi. Anybody on this forum own an mxu500i 2011?