2008 HiSun 700cc back-fire upon deceleration issue

[GreenThumb914]

Hi HiSun Forum Group.

I am a new member looking for some guidance on how to properly adjust the carburetor.  My general (and maybe flawed) understanding is that there is supposed to be both a Fuel side and an Air side adjustment screw on most Quad & Side by Side carbs. My HiSun 700 seems to have finger-spin idle adjusting screw  (easily accessible on the driver's side of the carb) and a Carburetor Pilot Screw (not easily accessible, directly underneath the carb but above the engine head).  My instinct tells me that the Pilot screw is for adjusting the Fuel as it is on the Fuel side of the Carb.  I don't see any adjusting screws on the Air side of the carb.  I've adjusted the pilot screw several times but never successfully eliminating the back-fire upon deceleration issue.  Any intel on my apparently missing Air adjusting screw and or back-fire issue is greatly appreciated.

Additional notes: My spark plug and fuel filter is new and I only use non-ethanol fuel. Manufacturer of the motor is Chongqing Huansong Industries Group Co., Ltd. Engine Family: 8TMTX.700A10

[Mech]

Leaking exhaust at the head, or muffler, or a modified "high flow"(empty) muffler.

Does it idle ok ? Does the mixture screw change the mixture from lean to rich in a half to one turn ? Have you been adjusting the idle speed and mixture to get the best idle at the slowest speed possible. with the idle speed backed right down ?

Edited November 8, 2022 by Mech