New Mule runs like shit when warm

keseymou · February 15, 2015

I have had my 2014 leftover for just 2 weeks. Seems like when I use it to plow for a few hours, it wont idle. I can normally smell a strange odor, and I have to feather the throttle peddle to keep it running. Its been back to the shop 2 times in the past week or so, and they claim it runs fine with them. I told them it does it when I use it for approx 1.5-2 hours. According to the hour meter, they used the machine for about .7 hours,,, so of course it didnt act up on them. I think its a dirty carb, but they arent willing to tear it apart to clean it.

Help

keseymou · February 16, 2015

Wow. This is the 3rd forum I have joined to ask questions,,, and it seems as tho nobody knows anything.

kenfain · March 7, 2015

Have you tried anything to narrow the problem down, such as fuel pressure? Does it continue to run badly, after it's been shut down for awhile?

When you have a problem like this, you'll have many different systems that are suspect. The carb does seem likely, but it could possibly be a fuel pump, or filter. Or maybe the electrical system, once warmed up completely, could cause the misfiring.

Personally I'd be setting up to read that fuel pressure before and after it starts acting up.

keseymou · March 7, 2015

The Dealer wasnt helpful. I troubleshot the problem and found the rubber gasket in the fuel cap was blocking the vent hole, which was pressurizing the intake. Problem is fixed.

Southernmost · August 7, 2015

Similar problem. But story is, mule 550( early model), vacuum driven pump. Was set up for about 2 yrs and gas tank rusted, carb rotted. I replaced the bowl gasket, cleaned the carb, replaced all fuel and vaccum lines. Mule cranks, runs smoothe for about 3 sec then sputters and dies. Will not run at half throttle, only wide open and idle after 30 sec. I have replaced the vaccum line, cleaned and gapped the plug, recleaned the carb, and still doing it. Any new suggestions?

Southernmost · August 19, 2015

Hey, just an update. I have cleaned the carb like three or four times so the carbs virtually spotless. I replaced the plug and still the mule 550 runs bad. It idles with a little studder, when I press the gas it dies like the choke is pulled. But if I go from idle to WOT it runs fine. I just can't run wide open all the time. Someone suggested the throttle linkage was off but I haven't messed with it. Any help? Once again it has new fuel pump, gas tank washed out, new fuel and vacuum lines, new plug.