SECTOR 250 RUNS BUT WON’T IDLE

A DIRT WHEELS FAN WRITES: “I purchased a used 2019 Hisun Sector 250 for my son. The previous owner stated they could not get the idle adjusted. This led me to believe that the machine was carbureted and I could either adjust or clean the carburetor. Well, as it turned out it is fuel injected, and I don’t understand why it will not idle. The only things I see odd are, no matter how hard my son runs the machine, there is only a single bar on the coolant temperature gauge and the sparkplug is always black. Maybe that is the cause?” – Bruce Dolan, Greig, NY

OUR PRO ANSWER: You may be onto something with those observations! The EFI computer determines the fuel mixture from information provided by the ECT (Engine Coolant Temperature) sensor.  Since your spark plug indicates a rich mixture and your engine temp reads cold, the ECT #1 may be bad. Generally, a cold engine requires more fuel,  and, if the engine is warm but the ECT says the engine is cold, then the fuel mixture being fed to the engine is too rich, like the choke being on. And this is why the motor will not idle. To test the #1 ECT, you will need a VOM (Volt Ohm Meter). Remove the #1 ECT from the cylinder head. At room temperature and up to 248 ± 5.4 °F, there should be no continuity. Above that temperature and there should be continuity. And on the cool down, below 235.4 °F, the continuity should disappear. If the readings you obtained are outside these temperatures, replace the ECT. A replacement ECT is available here: https://www.amazon.com/Coolant-Temperature-Coleman-Massimo-Challenger/dp/B092VTL417

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