UT400 cutting out mid throttle

[Homeowner A]

Have an issue all the sudden where the UTV will cut out randomly mid range throttle and under load.  Light consistent throttle on fairly flat ground no problems.  If you quickly change throttle position sometimes it will bog down and cut out, splutter, etc.  Floor it or let off and it may do just fine.  Going up a hill and adding more throttle as the incline demands, will cut out splutter and smell unburnt fuel.  So far doesn't ever completely quit.  If you let off it will idle just fine.  A lot of times if you floor it, it will pick up and even get a boost of power.  Changed to a slightly hotter plug to see if that would make a difference, but it didn't .  Any ideas what might be going on and what to try next?  

[Homeowner A]

Anyone have any input here?  

[W B]

Not familiar with your machine but sounds like an air leak to me. Check all gaskets and hoses.

 

[Joe Breaux]

Is it carb or Efi?

[Homeowner A]

  On 1/4/2025 at 4:45 PM, Joe Breaux said:

Is it carb or Efi?

Expand  

EFI - a new fuel injector has made all the difference.  

[Joe Breaux]

Glad you found the problem. Because these don't run every day and ethanol fuel is crap, injectors on efi and jets on carbs get clogged 

[Homeowner A]

Replaced injector and it has been running well until yesterday. Now it’s cutting out again mid throttle when it gets up to full temp. Possibly misfiring too did smell some unburnt fuel at one point when it would cut out.  Light throttle or flooring it and it does fine. I replaced the injector again but no improvement. Any ideas? What should I look at next?