I finally got the O-ring in and I ordered a main jet in just to make sure. I removed the Carburetor from the engine and put it on the bench for dissection. I drained the bowl of gas and removed the bowl. I removed the main jet and replaced it with my new 112 jet. I inspected everything and put the bowl back on. I replaced the cracked O-ring with a new one. After reinstalling the carb and hooking everything back up, I cranked the bike up. It idles perfectly! I back it out of the garage and shift into first gear and off I go. Sputter..... sputter.... same problem. Hum...... I pull the plug and the plug is black and sooty. Running rich...... I drop the needle on the throttle valve all the way and try it again. Same result. Maybe the choke is stuck open? I check the choke to verify it is sliding in the cylinder fine. I adjust the choke cable out as far as it will go and re-install it. Same issue. I check the timing which is perfect. The carburetor seems fine. Only one problem could exist if it is a carburetor problem. The main air jet must be plugged. The air jet is a small hole that starts just under the main air intake on the carb and continues into the main jet primary. The air jet is the metering circuit between 1/4 to 3/4 throttle. With it being plugged the fuel does not atomize and the raw fuel will not burn properly.
I disassemble the entire carb and let it soak for twenty minutes in parts cleaner. After rinsing it, I use my small needle pick and insert it into the air jet primary. As expected it is plugged with gunk. I clean it well and squirt some carb cleaner through it.
I re-assemble the carb and put it back on the quad. I turn the gas on and allow the bowl to fill. It starts up as before but this time as I give it the throttle it takes off with no stutter or back fire!
