2010 Hisun 700 - wont idle and running rough

[William]

Hello all 

I have a 2010 hisun 700 carb model, it was running great all spring during covid then all of a sudden it started stalling at low RPMs and now wont idle at all.  It will run if i keep my foot on the gas but its just doesn't sound right so I stopped running it. 

My first thought was bad fuel, we had a lot of rain this spring and thought maybe condensation so i drained the tank, changed all the filters and even got new gas line and removed the second tank just to be safe after reading about not need it, still nothing.

Cleaned the carb and still nothing

Bought a new carb just to be safe as they are cheap enough and still running rough

Found the other issue with the Second Air Supply and a hose that comes from the exhaust that was broken, bought a new one of those and tried to attach it and it disintegrated in my hands when i touched it so i tried to attach it to the 1/2 that was left just trying to see if it would complete the vacuum but still ran rough

Changed the oil and filter too just in case it was that but still nothing

Took the new carb apart and cleaned it just to be safe, took out the air/fuel cover which is the stupidest thing when they send it to you without a screw driver to take the cover off so drilled it until a screwdriver could unscrew it - turned it all the way in then backed it out 2 full turns (like everyone says is the starting point) and it ran worse.

Bought a new coil just in case the spark was the issue, installed that and getting good spark so not that.

Bought a new air filter and have to still put that in so will try that tomorrow

Anything I missing, I have tried all i know and there is not enough youtube videos on repairs on these carts so looking for you folks to see if you can assist and give me some guidance on this issue

Thanks!!

[Travis]

Is the engine surging? RPM's Raise and Lower quickly?

[William]

No it won’t idle at all and when I push the gas and get it running it’s running semi smooth no surging but as soon as I drop rpms below 1600 it stalls

[Travis]

I see that the 700 has an Idle Air control valve...could be that, it happened on our car onetime, wouldn't idle,. i would locate it and see if there is way to test it.

https://www.ebay.com/itm/Idle-Air-Control-Valve-IAC-Delphi-Sensor-For-HiSUN-400-500-700-800-1000-UTV-/363085163926

[William]

That is for the EFI models I have a carb so dont have one

[kenfain]

There's several things that you can try. Like checking for blockage of the crankcase ventilation tube. Or the return fuel line. I assume that you've played with the air mix screw, beyond just setting it at two turns.